Information recording medium, recording apparatus, reproduction apparatus, recording method and reproduction method

ABSTRACT

An information recording medium is provided that includes a data area for recording user data and a defect management area for recording a defect list for managing N number of defect areas existing in the data area, where N is an integer satisfying N≧0. The defect list includes two or more blocks, and further includes a header located at a fixed position in the defect list and N number of defect entries, located subsequent to the header, including position information on the respective positions of the N number of defect areas. An anchor is located subsequent to the defect entries, and the header includes first update times information representing the number of times that the defect list has been updated. The anchor includes second update times information representing the number of times that the defect list has been updated.

This application is a continuation of U.S. patent application Ser. No.11/279,821 filed Apr. 14, 2006, which is a continuation of U.S.application Ser. No. 11/279,815 filed Apr. 14, 2006, now U.S. Pat. No.7,257,057, which is a continuation of U.S. patent application Ser. No.10/377,835, filed Mar. 3, 2003, now U.S. Pat. No. 7,031,239.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an information recording medium, arecording apparatus, a reproduction apparatus, a recording method, and areproduction method, providing improved information reliability. Morespecifically, the present invention relates to an information recordingmedium, a recording apparatus, a reproduction apparatus, a recordingmethod, and a reproduction method, allowing for updating of a defectlist having a size of 2ECC (Error Correction Code) or larger anddeletion of a defect entry.

2. Description of the Related Art

Recently, large capacity replaceable information recording media anddisc drive apparatuses for driving such information recording media arebecoming more and more popular. As large capacity replaceableinformation recording media, optical discs such as, for example, DVDs(Digital Versatile Discs) are well known. A disc drive apparatusirradiates an optical disc with laser light and thus forms very smallpits in the optical disc so as to record information. The disc driveapparatus also irradiates an optical disc with laser light andreproduces a change in the reflectance caused by the pits asinformation. Large capacity replaceable information recording media aresuitable to a disc drive apparatus performing information recording andreproduction in this manner. However, since the optical discs arereplaceable, a defect caused by dust or scratches may exist on arecording surface thereof.

In order to guarantee the reliability of information recorded orreproduced by the disc drive apparatus, it is necessary to performdefect management of managing a defect existing on the optical disc. Thedefect management used for a conventional disc drive apparatus isdescribed in the physical standards of DVD-RAM (e.g., “DVDSpecifications for Rewritable Disc (DVD-RAM) Part 1 PHYSICALSPECIFICATIONS Version 2.0”; hereinafter, referred to as the “DVD-RAMStandards”). Chapter 5 of the DVD-RAM Standards includes a descriptionon the layout of a disc.

FIG. 12 shows a data structure of an information recording medium 1200according to the DVD-RAM Standards.

The information recording medium 1200 includes a lead-in area 1201 forrecording information regarding the disc, a data area 1202 for recordinguser data, and a lead-out area 1203 showing the termination position ofthe user data.

The lead-in area 1201 includes DMA1 (Defect Management Area) and DMA2for recording defect management information used for managing a defectarea existing in the data area 1202, and reserved areas 1204 and 1205for future expansion.

The data area 1202 includes a user area 1206 for recording user data anda spare area 1207. When there is a defect area in the user area 1206,the user data which is to be recorded in the defect area is recorded inthe spare area 1207 instead of a portion of the user area 1206corresponding to the defect area.

The lead-out area 1203 includes DMA3 and DMA4 for recording defectmanagement information used for managing a defect area existing in thedata area 1202, and reserved areas 1208 and 1209 for future expansion,like the lead-in area 1201.

DMA1 through DMA4 have the same defect management information recordedin multiplex. The reason for this is that the information recorded inDMA1 through DMA4 cannot be a target of defect management. Even if someof DMA1 through DMA4 have a defect area and the information recorded onthe information recording medium cannot be reproduced, as long as atleast one of DMA1 through DMA4 is defect-free, the defect managementinformation recorded in that area can be normally reproduced.Accordingly, loss of user data is prevented, which improves reliability.

DMA1 includes a DDS (Data Definition Structure) 1210, a PDL (PrimaryDefect List) 1211, and an SDL (Secondary Defect List) 1212.

The DDS 1210 includes information regarding a partition defining the PDL1211 and the SDL 1212.

The PDL 1211 is position information (list) of defect areas (forexample, defect sectors) detected in the user area 1206 and the sparearea 1207 at the time of shipping of the information recording medium,i.e., at the time of initialization of the information recording medium.This list basically does not change unless the information recordingmedium is subjected to physical formatting.

According to the DVD-RAM Standards, the total size of the DDS 1210 andthe PDL 1211 fits in one ECC (Error Correction Code) block. The size ofthe SDL 1212 also fits in one ECC block. An ECC block is a unit of errorcorrection in DVD-RAM, and has a size of 32 kbytes in 16 sectors (eachsector has a size of 2 kbytes). This size of one ECC block will bereferred to as “1ECC size”.

FIG. 13 shows a detailed data structure of the SDL 1212.

Unlike the PDL 1211, the SDL 1212 is information (list) which changeswhen a defect area (for example, defect sector) is detected duringrecording or reproduction. When a defect area is detected, the SDL 1212is written in each of DMA1 through DMA4 at a timing appropriate to thedisc drive apparatus used.

The SDL 1212 includes a header 1301, a first defect entry 1302, a seconddefect entry 1303, . . . , an Nth defect entry 1304, and an unused area1305.

The header 1301 includes, for example, an identifier which representsthat the area is the SDL 1212, the total number of defect entries (N inthe case of FIG. 13), and the number of times the SDL 1212 has beenupdated.

The first defect entry 1302 includes first defect position information1306 showing the position of a defect area existing in the user area1206 and first substitute position information 1307 showing the positionof a part of the spare area 1207 in which the user data has beenrecorded instead of the defect area (for example, a substitute sector).The second defect entry 1303 includes second defect position informationand second substitute position information. The Nth defect entryincludes Nth defect position information and Nth substitute positioninformation. Each of the defect position information and the substituteposition information is generally a sector number.

The unused area 1305 exists in the case where the total size of theheader 1301 and the first through Nth defect entries 1302 through 1304is less than 1ECC size. In this case, padding data (for example, 0)which is meaningless information is recorded in the unused area 1305.

There is a risk that while the disc drive apparatus is writing the SDL1212 in DMA1 through DMA4 of the information recording medium 1200, thepower of the disc drive apparatus may be turned off and processing maybe interrupted. In such a case, the disc drive apparatus determines theupdate result of the defect management areas (DMA1 through DMA4) by thefollowing procedure.

(1) Error correction is performed on the SDL 1212 having 1ECC size. Whenthe error correction is accurately performed, the SDL 1212 is determinedto have been updated normally.

(2) The step of (1) is performed on all the SDLs included in DMA1through DMA4.

(3) Regarding all the SDLs determined to have been updated normally instep (2), the numbers of updates of the SDLs included in the header arecompared with one another. The SDL having the largest number of updatesis determined to be the correct SDL (latest SDL).

As described above, when the size of the SDL 1212 is 1ECC size, thedetermination of the correct SDL can be performed accurately even whenthe power of the disc drive apparatus is turned off. Thus, thereliability of user data is guaranteed with no user data being lost.

Recently, as the amount of information to be recorded on informationrecording media is increased, high density recording technology andlarge capacity technology have remarkably improved. For example, usingblue lasers, information recording media having a larger capacity thanthat of conventional optical discs are now under development. Since suchan information recording medium allows a larger capacity of informationto be recorded thereon, the size of the SDL is larger than 1ECC size. Aslong as the size of the SDL is 1ECC size or smaller as according to theDVD-RAM Standards, no problem arises. When the size of the SDL exceeds1ECC size, the following problems occur. In the following case, the sizeof the SDL is assumed to be 4ECC size.

It is assumed that the following occurs to one DMA (for example, DMA1)as a result of the size of the SDL becoming 4ECC size instead of theconventional 1ECC size.

-   -   The header is completely updated.    -   The SDL is updated up to 2ECC blocks, and the power of the disc        drive apparatus is turned off exactly when the third ECC block        is starting to be updated.

In this case, according to the conventional method of determining theSDL update result, error correction in units of 1ECC is normallyperformed. Comparing the number of updates of the SDL in DMA1 with thatof the SDLs in DMA2 through DMA4, the number of updates of the SDL inDMA1 is maximum. Therefore, although the updating of the SDL in DMA1fails in the middle, the SDL in DMA1 is erroneously determined to be thenormal, latest SDL.

One solution proposed to solve this problem is to add a header for eachECC block of the SDL having 4ECC size. Each header includes, forexample, an identifier which represents that the area is the SDL, thetotal number of defect entries, and the number of updates of the SDL.

FIG. 14 shows a data structure of an SDL 1400 having 4ECC size.

The SDL 1400 includes a first ECC block 1401, a second ECC block 1402, athird ECC block 1403, and a fourth ECC block 1404.

The first ECC block 1401 includes a header 1405, a first defect entry1406, a second defect entry 1407, an (M−1)th defect entry 1408, and anMth defect entry 1409.

The second ECC block 1402 includes a header 1410, an (M+1)th defectentry 1411, . . . , an Nth defect entry 1412, and an unused area 1413.

The third ECC block 1403 includes a header 1414 and an unused area 1415.

The fourth ECC block 1404 includes a header 1416 and an unused area1417.

The headers 1405, 1410, 1414 and 1416 each include, for example, anidentifier which represents that the area is the SDL, the total numberof defect entries, and the number of updates of the SDL. The firstthrough Nth defect entries 1406 through 1409, 1411 and 1412 each includedefect position information and substitute position information. In theunused areas 1413, 1415 and 1417, padding data (for example, 0) which ismeaningless information is recorded.

In this case, the disc drive apparatus determines the update result ofthe defect management areas (DMA1 through DMA4) by the followingprocedure.

(1) For the SDL 1400 having 4ECC size, error correction is performed onthe first ECC block 1401. When the error correction is accuratelyperformed, the first ECC block 1401 is determined to have been updatednormally. This step is performed on the second through fourth ECC blocks1402 through 1404 in the SDL 1400. When the error correction on thefirst through fourth ECC blocks 1401 through 1404 is accuratelyperformed, the step (2) is performed.

(2) The numbers of updates of the headers 1405, 1410, 1414 and 1416respectively added to the first through fourth ECC blocks 1401 through1404 are compared with one another. When the numbers of updates of theheaders 1405, 1410, 1414 and 1416 are all of the same value, the SDL1400 is determined to have been updated normally.

(3) Steps (1) and (2) are performed on all the SDLs in DMA2 throughDMA4.

(4) Regarding the SDLs determined to have been updated normally in step(3), the numbers of updates of the SDLs included in the header arecompared with one another. The SDL having the largest number of updatesis determined to be the correct SDL (latest SDL).

As described above, when the size of the SDL 1400 exceeds 1ECC size, aheader is provided for each 1ECC block of the SDL, so that the correctSDL can be determined even when the power of the disc drive apparatus isturned off. Thus, the reliability of user data is guaranteed with nouser data being lost.

There is another conventional technology for improving the reliabilityof data (see, for example, Japanese Laid-Open Publication No. 8-293187).

FIG. 15 shows a data structure of another conventional informationrecording medium 1500.

The structure of the information recording medium 1500 is identical withthe structure of the information recording medium 1200 except for thestructure of an SDL 1501 and except that the size of the SDL 1501 is notlimited to 1ECC size. Regarding FIG. 15, identical elements previouslydiscussed with respect to FIG. 12 bear identical reference numerals andthe detailed descriptions thereof will be omitted.

The SDL 1501 includes a defect list identifier 1502 which representsthat the area is the SDL 1501, a reserved field 1503 for futureexpansion, first update information 1504 and second update information1510 for determining whether defect management information is old ornew, a registered defect number 1505 which represents the number ofdefect sectors registered in the SDL 1501, first defect positioninformation 1506 and second defect position information 1508 whichrepresent the position of a defect sector, first substitute positioninformation 1507 and second substitute position information 1509 whichrepresent the position of a substitute sector for substituting thedefect sector, and an unused field 1511 for registering defect sectorswhich may be detected in the future. The first update information 1504and the second update information 1510 are, for example, numbers oftimes of recording. As long as the SDL 1501 is updated normally, thecontent of the first update information 1504 and the content of thesecond update information 1510 are identical to each other.

In this case, the disc drive apparatus determines the update result ofthe defect management areas (DMA1 through DMA4) by the followingprocedure.

(1) Regarding the SDL 1501, the content of the first update information1504 and the content of the second update information 1510 are comparedwith one another. When the content of the first update information 1504and the content of the second update information 1510 are identical toeach other, the SDL 1501 is determined to have been updated normally.

(2) Step (1) is performed on all the SDLs in DMA2 through DMA4.

(3) Regarding the SDLs determined to have been updated normally in step(2), the contents of the update information in the SDLs are comparedwith one another. The SDL having the largest amount of updateinformation is determined to be the correct SDL (latest SDL).

As described above, as long as the first update information and thesecond update information added to the SDL included in one of DMA1through DMA4 are correctly read, the determination of the correct SDLcan be performed accurately, regardless of the size of the SDLs.

However, the SDL 1400 shown in FIG. 14 has the following problems. Aheader needs to be added to all of the four ECC blocks included in theSDL 1400. This lowers the processing efficiency of updating the SDL1400. In addition, a header (for example, the header 1410) is providedbetween one defect entry (for example, the Mth defect entry 1409) andanother defect entry (for example, the (M+1)th defect entry 1411). Dueto this structure, the operations of, for example, searching for,adding, and deleting a defect entry are complicated.

The information recording medium 1500 shown in FIG. 15 has the problemthat the second update information 1511 may not be correctly read.

FIG. 16 shows data structures of defect lists in various states of theSDL 1501 in the information recording medium 1500 shown in FIG. 15. Part(a) shows a data structure of a pre-update defect list. Part (b) shows adata structure of a defect list which was updated normally. Part (c)shows a data structure of a defect list which was not updated normally.With reference to FIG. 16, how the SDL 1501 is updated, in the casewhere a sector which was previously determined as being registered as adefect area and then determined as being normal later, will bedescribed.

The data structure of the SDL 1501 shown in part (a) of FIG. 16 is thesame as that shown in FIG. 15. In part (a) of FIG. 16, the content ofthe first update information 1504 and the second update information 1510are both M, and the registered defect number 1505 is 2.

Part (b) of FIG. 16 shows a post-update data structure of the SDL 1501in the case where the SDL 1501 is updated normally. The content of thefirst update information 1504 is updated from M to M+1. The registereddefect number 1505 is updated from 2 to 1. The position information ofthe defect sector which has been determined as being normal (seconddefect position information 1508) and the position information of thesubstitute sector for substituting that sector (second substituteposition information 1509) are deleted. Thus, the first defect positioninformation 1506 and the first defect position information 1507 areleft. The content of the second update information 1510 is updated fromM to M+1, like the first update information 1504. The second updateinformation 1510 is located subsequent to the first substitute positioninformation 1507. The unused field 1511 is increased by the sizecorresponding to the second defect position information 1508 and thesecond substitute position information 1509 which have been deleted.

Part (c) of FIG. 16 shows a post-update data structure of the SDL 1501in the case where the SDL 1501 is not updated normally. It is assumedthat immediately after the registered defect number 1505 is updated, thedisc drive apparatus is turned off. In this case, the first updateinformation 1504 and the registered defect number 1505 are updatednormally as in part (b) of FIG. 16. However, the second defect positioninformation 1508, the second substitute position information 1509, thesecond update information 1510 and the unused field 1511 remain the sameas those in the pre-update data structure shown in part (a) of FIG. 16.

In the case of the data structure shown in part (c) of FIG. 16,determination on the update result is performed. The disc driveapparatus uses, for example, the updated registered defect number 1505to read the second defect position information 1508 as the second updateinformation 1510. The disc drive apparatus compares the content of thefirst update information 1504 and the content of the second defectposition information 1508 read as the second update information 1510.When the content of the first update information 1504 and the content ofthe second defect position information 1508 unfortunately match eachother, the disc drive apparatus determines that the SDL 1501 has beenupdated normally even though the updating of the SDL 1501 was a failure.

In the case where the information recording medium 1500 shown in FIG. 15considers error correction of the size of 1ECC and the size of the SDL1501 does not exceed 1ECC size, the problem described above withreference to part (c) of FIG. 16 does not occur. However, when the sizeof the SDL 1501 exceeds 1ECC size, the above-described problem occurs.

SUMMARY OF THE INVENTION

According to one aspect of the invention, an information recordingmedium includes a data area for recording user data, and a defectmanagement area for recording a defect list for managing N number ofdefect areas existing in the data area, where N is an integer satisfyingN≧0. The defect list includes a header located at a fixed position inthe defect list, N number of defect entries respectively includingposition information on positions of the N number of defect areas, andan anchor. The header, the N number of defect entries, and the anchorare located in this order in the defect list. The header includes adefect list identifier for identifying the defect list, first updatetimes information representing the number of times which the defect listhas been updated, and a defect entry number representing the number ofthe N number of defect entries. The anchor includes an anchor identifierfor identifying the anchor of the defect list, and second update timesinformation representing the number of times which the defect list hasbeen updated.

In one embodiment of the invention, the defect list includes at leasttwo blocks, and the defect list is recorded in units of one block.

According to another aspect of the invention, a recording apparatus forrecording information on an information recording medium is provided.The information recording medium includes a data area for recording userdata, and a defect management area for recording a defect list formanaging N number of defect areas existing in the data area, where N isan integer satisfying N≧0. The defect list includes a header located ata fixed position in the defect list, N number of defect entriesrespectively including position information on positions of the N numberof defect areas, and an anchor. The header, the N number of defectentries, and the anchor are located in this order in the defect list.The header includes a defect list identifier for identifying the defectlist, first update times information representing the number of timeswhich the defect list has been updated, and a defect entry numberrepresenting the number of the N number of defect entries. The anchorincludes an anchor identifier for identifying the anchor of the defectlist, and second update times information representing the number oftimes which the defect list has been updated. The recording apparatusincludes a recording section for recording the information on theinformation recording medium, a storage section for storing theinformation to be recorded on the information recording medium, and alatest defect list, and a control section for controlling execution ofdefect management processing which is performed using the recordingsection and the storage section. The latest defect list includes alatest header, P number of latest defect entries, and a latest anchor,wherein P is an integer satisfying P≧0 where P=N or P≠N. The latestheader includes first latest update times information and a latestdefect entry number P. The latest anchor includes second update timesinformation having a content identical to that of the first update timesinformation. The defect management processing includes the steps of (a)determining (i) whether another defect area exists in the data area,(ii) whether a normal defect area exists among the N number of defectareas, or (iii) neither (i) nor (ii) is the case, (b) when it isdetermined in the step (a) that another defect area exists in the dataarea, or that a normal defect area exists among the N number of defectareas, updating the P number of latest defect entries into P′ number oflatest defect entries, where P′ is an integer satisfying P′≧0 where P=P′or P≠P′; and updating the latest defect entry number from P to P′; (c)incrementing, by one, each of the first latest update times informationand the second latest update times information, and (d) recording thelatest defect list updated in the steps (b) and (c) in the defectmanagement area.

In one embodiment of the invention, the step (d) includes the step ofrecording the updated latest defect list in the defect management areain the order of the updated latest header, the updated P′ number oflatest defect entries, and the updated latest anchor, or in the order ofthe updated latest anchor, the updated P′ number of latest defectentries, and the updated latest header.

In one embodiment of the invention, the step (b) includes the step of,when it is determined in the step (a) that another defect area exists inthe data area, adding another defect entry to the latest defect list.

In one embodiment of the invention, the step (b) includes the step of,when it is determined in the step (a) that a normal defect area existsamong the N number of defect areas, deleting a defect entry includingposition information on a position of the normal defect area from the Pnumber of latest defect entries.

In one embodiment of the invention, the information recording mediumfurther includes another defect management area for recording a defectlist having a content identical to that of the defect list recorded inthe defect management area. The control section controls execution ofthe step (d) for the another defect management area.

According to still another aspect of the invention, a recording methodfor recording information on an information recording medium isprovided. The information recording medium includes a data area forrecording user data, and a defect management area for recording a defectlist for managing N number of defect areas existing in the data area,where N is an integer satisfying N≧0. The defect list includes a headerlocated at a fixed position in the defect list, N number of defectentries respectively including position information on positions of theN number of defect areas, and an anchor. The header, the N number ofdefect entries, and the anchor are located in this order in the defectlist. The header includes a defect list identifier for identifying thedefect list, first update times information representing the number oftimes which the defect list has been updated, and a defect entry numberrepresenting the number of the N number of defect entries. The anchorincludes an anchor identifier for identifying the anchor of the defectlist, and second update times information representing the number oftimes which the defect list has been updated. The recording is performedusing a latest defect list. The latest defect list includes a latestheader, P number of latest defect entries, and a latest anchor, whereinP is an integer satisfying P≧0 where P=N or P≠N. The latest headerincludes the first update times information and a latest defect entrynumber P. The latest anchor includes second update times informationhaving a content identical to that of the first update timesinformation. The recording method includes the steps of (a) determining(i) whether another defect area exists in the data area, (ii) whether anormal defect area exists among the N number of defect areas, or (iii)neither (i) nor (ii) is the case, (b) when it is determined in the step(a) that another defect area exists in the data area, or that a normaldefect area exists among the N number of defect areas, updating the Pnumber of latest defect entries into P′ number of latest defect entries,where P′ is an integer satisfying P′≧0 where P=P′ or P≠P′; and updatingthe latest defect entry number from P to P′; (c) incrementing, by one,each of the first latest update times information and the second latestupdate times information, and (d) recording the latest defect listupdated in the steps (b) and (c) in the defect management area.

In one embodiment of the invention, the step (d) includes the step ofrecording the updated latest defect list in the defect management areain the order of the updated latest header, the updated P′ number oflatest defect entries, and the updated latest anchor, or in the order ofthe updated latest anchor, the updated P′ number of latest defectentries, and the updated latest header.

In one embodiment of the invention, the step (b) includes the step of,when it is determined in the step (a) that another defect area exists inthe data area, adding another defect entry to the latest defect list.

In one embodiment of the invention, the step (b) includes the step of,when it is determined in the step (a) that a normal defect area existsamong the N number of defect areas, deleting a defect entry includingposition information on a position of the normal defect area from the Pnumber of latest defect entries.

In one embodiment of the invention, the information recording mediumfurther includes another defect management area for recording a defectlist having a content identical to that of the defect list recorded inthe defect management area. The control section controls execution ofthe step (d) for the another defect management area.

According to still another aspect of the invention, a reproductionapparatus for reproducing information recorded on an informationrecording medium is provided. The information recording medium includesa data area for recording user data, and a defect management area forrecording a defect list for managing N number of defect areas existingin the data area, where N is an integer satisfying N≧0. The defect listincludes a header, N number of defect entries respectively includingposition information on positions of the N number of defect areas, andan anchor. The header located at a fixed position in the defect list,the N number of defect entries, and the anchor are located in this orderin the defect list. The header includes a defect list identifier foridentifying the defect list, first update times information representingthe number of times which the defect list has been updated, and a defectentry number representing the number of the N number of defect entries.The anchor includes an anchor identifier for identifying the anchor ofthe defect list, and second update times information representing thenumber of times which the defect list has been updated. The reproductionapparatus includes a reproduction section for reproducing theinformation recorded on the information recording medium, a storagesection for storing the reproduced information, and a control sectionfor controlling execution of defect management processing which isperformed using the reproduction section and the storage section, thecontrol section having an inherent defect list identifier foridentifying the defect list and an inherent anchor identifier foridentifying the anchor of the defect list. The defect managementprocessing includes the steps of (a) reproducing the defect listidentifier, the defect entry number, and the first update timesinformation which are included in the header, and determining whether ornot a content of the inherent defect list identifier matches a contentof the reproduced defect list identifier, (b) calculating a position ofthe anchor in the defect list using the reproduced defect entry numberwhen it is determined in the step (a) that the content of the inherentdefect list identifier matches the content of the reproduced defect listidentifier, (c) reproducing the anchor identifier and the second updatetimes information based on the calculated position of the anchor, anddetermining whether or not a content of the inherent anchor identifiermatches a content of the reproduced anchor identifier, (d) determiningwhether or not a content of the first update times information matches acontent of the second update times information when it is determined inthe step (c) that the content of the inherent anchor identifier matchesthe content of the reproduced anchor identifier, and (e) specifying thedefect list recorded in the defect management area as the latest defectlist when it is determined in the step (d) that the content of the firstupdate times information matches the content of the second update timesinformation.

In one embodiment of the invention, the information recording mediumfurther includes another defect management area for recording a defectlist having a content identical to that of the defect list recorded inthe defect management area. The control section controls execution ofthe defect management processing for the another defect management area.The step (e) includes the steps of (e₁) performing the steps (a) through(d) for the another defect management area, and (e₂) specifying thedefect list including the update times information having a largestnumber of updates as the latest defect list.

According to still another aspect of the invention, a reproductionmethod for reproducing information recorded on an information recordingmedium is provided. The information recording medium includes a dataarea for recording user data, and a defect management area for recordinga defect list for managing N number of defect areas existing in the dataarea, where N is an integer satisfying N≧0. The defect list includes aheader, N number of defect entries respectively including positioninformation on positions of the N number of defect areas, and an anchor.The header located at a fixed position in the defect list, the N numberof defect entries, and the anchor are located in this order in thedefect list. The header includes a defect list identifier foridentifying the defect list, first update times information representingthe number of times which the defect list has been updated, and a defectentry number representing the number of the N number of defect entries.The anchor includes an anchor identifier for identifying the anchor ofthe defect list, and second update times information representing thenumber of times which the defect list has been updated. The reproductionmethod includes the steps of (a) reproducing the defect list identifier,the defect entry number, and the first update times information whichare included in the header, and determining whether or not a content ofan inherent defect list identifier for identifying the defect listmatches a content of the reproduced defect list identifier, (b)calculating a position of the anchor in the defect list using thereproduced defect entry number when it is determined in the step (a)that the content of the inherent defect list identifier matches thecontent of the reproduced defect list identifier, (c) reproducing theanchor identifier and the second update times information based on thecalculated position of the anchor, and determining whether or not acontent of an inherent anchor identifier for identifying the anchor ofthe defect list matches a content of the reproduced anchor identifier,(d) determining whether or not a content of the first update timesinformation matches a content of the second update times informationwhen it is determined in the step (c) that the content of the inherentanchor identifier matches the content of the reproduced anchoridentifier, and (e) specifying the defect list recorded in the defectmanagement area as the latest defect list when it is determined in thestep (d) that the content of the first update times information matchesthe content of the second update times information.

In one embodiment of the invention, the information recording mediumfurther includes another defect management area for recording a defectlist having a content identical to that of the defect list recorded inthe defect management area. The step (e) includes the steps of (e₁)performing the steps (a) through (d) for the another defect managementarea, and (e₂) specifying the defect list including the update timesinformation having a largest number of updates as the latest defectlist.

According to still another aspect of the invention, an informationrecording medium includes a data area for recording user data, and adefect management area for recording a defect list for managing N numberof defect areas existing in the data area, where N is an integersatisfying N≧0. The defect list includes a header located at a fixedposition in the defect list, N number of defect entries respectivelyincluding position information on positions of the N number of defectareas, and an anchor located at a fixed position in the defect list. Theheader, the N number of defect entries, and the anchor are located inthis order in the defect list. The header includes a defect listidentifier for identifying the defect list, first update timesinformation representing the number of times which the defect list hasbeen updated, and a defect entry number representing the number of the Nnumber of defect entries. The anchor includes second update timesinformation representing the number of times which the defect list hasbeen updated.

In one embodiment of the invention, the defect list includes at leasttwo blocks, and the defect list is recorded in units of one block.

According to still another aspect of the invention, a recordingapparatus for recording information on an information recording mediumis provided. The information recording medium includes a data area forrecording user data, and a defect management area for recording a defectlist for managing N number of defect areas existing in the data area,where N is an integer satisfying N≧0. The defect list includes a headerlocated at a fixed position in the defect list, N number of defectentries respectively including position information on positions of theN number of defect areas, and an anchor located at a fixed position inthe defect list. The header, the N number of defect entries, and theanchor are located in this order in the defect list. The header includesa defect list identifier for identifying the defect list, first updatetimes information representing the number of times which the defect listhas been updated, and a defect entry number representing the number ofthe N number of defect entries. The anchor includes second update timesinformation representing the number of times which the defect list hasbeen updated. The recording apparatus includes a recording section forrecording the information on the information recording medium, a storagesection for storing the information to be recorded on the informationrecording medium, and a latest defect list, and a control section forcontrolling execution of defect management processing which is performedusing the recording section and the storage section. The latest defectlist includes a latest header, P number of latest defect entries, and alatest anchor, wherein P is an integer satisfying P≧0 where P=N or P≠N.The latest header includes first latest update times information and alatest defect entry number P. The latest anchor includes second updatetimes information having a content identical to that of the first updatetimes information. The defect management processing includes the stepsof (a) determining (i) whether another defect area exists in the dataarea, (ii) whether a normal defect area exists among the N number ofdefect areas, or (iii) neither (i) nor (ii) is the case, (b) when it isdetermined in the step (a) that another defect area exists in the dataarea, or that a normal defect area exists among the N number of defectareas, updating the P number of latest defect entries into P′ number oflatest defect entries, where P′ is an integer satisfying P′≧0 where P=P′or P≠P′; and updating the latest defect entry number from P to P′; (c)incrementing, by one, each of the first latest update times informationand the second latest update times information, and (d) recording thelatest defect list updated in the steps (b) and (c) in the defectmanagement area.

In one embodiment of the invention, the step (d) includes the step ofrecording the updated latest defect list in the defect management areain the order of the updated latest header, the updated P′ number oflatest defect entries, and the updated latest anchor, or in the order ofthe updated latest anchor, the updated P′ number of latest defectentries, and the updated latest header.

In one embodiment of the invention, the information recording mediumfurther includes another defect management area for recording a defectlist having a content identical to that of the defect list recorded inthe defect management area. The control section controls execution ofthe step (d) for the another defect management area.

According to still another aspect of the invention, a recording methodfor recording information on an information recording medium isprovided. The information recording medium includes a data area forrecording user data, and a defect management area for recording a defectlist for managing N number of defect areas existing in the data area,where N is an integer satisfying N≧0. The defect list includes a headerlocated at a fixed position in the defect list, N number of defectentries respectively including position information on positions of theN number of defect areas, and an anchor located at a fixed position inthe defect list. The header, the N number of defect entries, and theanchor are located in this order in the defect list. The header includesa defect list identifier for identifying the defect list, first updatetimes information representing the number of times which the defect listhas been updated, and a defect entry number representing the number ofthe N number of defect entries. The anchor includes second update timesinformation representing the number of times which the defect list hasbeen updated. The recording is performed using a latest defect list. Thelatest defect list includes a latest header, P number of latest defectentries, and a latest anchor, wherein P is an integer satisfying P≧0where P=N or P≠N. The latest header includes the first update timesinformation and a latest defect entry number P. The latest anchorincludes second update times information having a content identical tothat of the first update times information. The recording methodincludes the steps of (a) determining (i) whether another defect areaexists in the data area, (ii) whether a normal defect area exists amongthe N number of defect areas, or (iii) neither (i) nor (ii) is the case,(b) when it is determined in the step (a) that another defect areaexists in the data area, or that a normal defect area exists among the Nnumber of defect areas, updating the P number of latest defect entriesinto P′ number of latest defect entries, where P′ is an integersatisfying P′≧0 where P=P′ or P≠P′; and updating the latest defect entrynumber from P to P′; (c) incrementing, by one, each of the first latestupdate times information and the second latest update times information,and (d) recording the latest defect list updated in the steps (b) and(c) in the defect management area.

In one embodiment of the invention, the step (d) includes the step ofrecording the updated latest defect list in the defect management areain the order of the updated latest header, the updated P′ number oflatest defect entries, and the updated latest anchor, or in the order ofthe updated latest anchor, the updated P′ number of latest defectentries, and the updated latest header.

In one embodiment of the invention, the information recording mediumfurther includes another defect management area for recording a defectlist having a content identical to that of the defect list recorded inthe defect management area. The method further comprises the step ofexecuting the step (d) for the another defect management area.

According to still another aspect of the invention, a reproductionapparatus for reproducing information recorded on an informationrecording medium is provided. The information recording medium includesa data area for recording user data, and a defect management area forrecording a defect list for managing N number of defect areas existingin the data area, where N is an integer satisfying N≧0. The defect listincludes a header located at a fixed position in the defect list, Nnumber of defect entries respectively including position information onpositions of the N number of defect areas, and an anchor located at afixed position in the defect list. The header, the N number of defectentries, and the anchor are located in this order in the defect list.The header includes a defect list identifier for identifying the defectlist, first update times information representing the number of timeswhich the defect list has been updated, and a defect entry numberrepresenting the number of the N number of defect entries. The anchorincludes second update times information representing the number oftimes which the defect list has been updated. The reproduction apparatusincludes a reproduction section for reproducing the information recordedon the information recording medium, a storage section for storing thereproduced information, and a control section for controlling executionof defect management processing which is performed using thereproduction section and the storage section, the control section havingan inherent defect list identifier for identifying the defect list. Thedefect management processing includes the steps of (a) reproducing thedefect list identifier, the defect entry number, and the first updatetimes information which are included in the header, and determiningwhether or not a content of the inherent defect list identifier matchesa content of the reproduced defect list identifier, (b) reproducing thesecond update times information included in the anchor and determiningwhether or not a content of the first update times information matches acontent of the second update times information when it is determined inthe step (a) that the content of the inherent defect list identifiermatches the content of the reproduced defect list identifier, and (c)specifying the defect list recorded in the defect management area as thelatest defect list when it is determined in the step (b) that thecontent of the first update times information matches the content of thesecond update times information.

In one embodiment of the invention, the information recording mediumfurther includes another defect management area for recording a defectlist having a content identical to that of the defect list recorded inthe defect management area. The control section controls execution ofthe defect management processing for the another defect management area.The step (c) includes the steps of (c₁) performing the steps (a) and (b)for the another defect management area, and (c₂) specifying the defectlist including the update times information having a largest number ofupdates as the latest defect list.

According to still another aspect of the invention, a reproductionmethod for reproducing information recorded on an information recordingmedium is provided. The information recording medium includes a dataarea for recording user data, and a defect management area for recordinga defect list for managing N number of defect areas existing in the dataarea, where N is an integer satisfying N≧0. The defect list includes aheader located at a fixed position in the defect list, N number ofdefect entries respectively including position information on positionsof the N number of defect areas, and an anchor located at a fixedposition in the defect list. The header, the N number of defect entries,and the anchor are located in this order in the defect list. The headerincludes a defect list identifier for identifying the defect list, firstupdate times information representing the number of times which thedefect list has been updated, and a defect entry number representing thenumber of the N number of defect entries. The anchor includes secondupdate times information representing the number of times which thedefect list has been updated. The reproduction method includes the stepsof (a) reproducing the defect list identifier, the defect entry number,and the first update times information which are included in the header,and determining whether or not a content of an inherent defect listidentifier for identifying the defect list matches a content of thereproduced defect list identifier, (b) reproducing the second updatetimes information included in the anchor and determining whether or nota content of the first update times information matches a content of thesecond update times information when it is determined in the step (a)that the content of the inherent defect list identifier matches thecontent of the reproduced defect list identifier, and (c) specifying thedefect list recorded in the defect management area as the latest defectlist when it is determined in the step (b) that the content of the firstupdate times information matches the content of the second update timesinformation.

In one embodiment of the invention, the information recording mediumfurther includes another defect management area for recording a defectlist having a content identical to that of the defect list recorded inthe defect management area. The step (c) includes the steps of (c₁)performing the steps (a) and (b) for the another defect management area,and (c₂) specifying the defect list including the update timesinformation having a largest number of updates as the latest defectlist.

Thus, the invention described herein makes possible the advantages ofproviding an information recording medium, a recording apparatus, areproduction apparatus, a recording method, and a reproduction method,allowing for updating of an SDL (defect list) having a size of 2ECC orlarger and deletion of a defect entry.

These and other advantages of the present invention will become apparentto those skilled in the art upon reading and understanding the followingdetailed description with reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a data structure of an information recording medium 100according to a first example of the present invention;

FIGS. 2A through 2D show detailed data structures of a header 121, afirst defect entry 122, an anchor 126, and an unused area 113;

FIG. 3 is a block diagram of a recording and reproduction apparatus 300according to a first example of the present invention;

FIG. 4 is a flowchart illustrating a procedure of defect managementprocessing for specifying the latest defect list in the first example;

FIG. 5 is flowchart illustrating a procedure of defect managementprocessing for updating the latest defect list in the first example;

FIG. 6 shows a data structure of a defect list, during the processingfor adding a defect entry in the first example, in various states of (a)before update, (b) when the defect list has been updated normally and(c) when the defect list has not been updated normally;

FIG. 7 shows a data structure of a defect list, during the processingfor deleting a defect entry in the first example, in various states of(a) before update, (b) when the defect list has been updated normallyand (c) when the defect list has not been updated normally;

FIG. 8 shows a data structure of a defect list, during the processingfor changing a defect entry in the first example, in various states of(a) before update, (b) when the defect list has been updated normallyand (c) when the defect list has not been updated normally;

FIG. 9 shows a data structure of an information recording medium 900according to a second example of the present invention;

FIG. 10 is a flowchart illustrating a procedure of defect managementprocessing for specifying the latest defect list in the second example;

FIG. 11 shows a data structure of a defect list, during the processingfor adding a defect entry in the second example, in various states of(a) before update, (b) when the defect list has been updated normallyand (c) when the defect list has not been updated normally;

FIG. 12 shows a data structure of an information recording medium 1200according to the DVD-RAM Standards;

FIG. 13 shows a detailed data structure of an SDL 1212;

FIG. 14 shows a data structure of an SDL 1400 having 4ECC size;

FIG. 15 is a data structure of another conventional informationrecording medium 1500; and

FIG. 16 shows a data structure of an SDL 1501 of the informationrecording medium 1500 shown in FIG. 15 in various states of (a) beforeupdate, (b) when the defect list has been updated normally and (c) whenthe defect list has not been updated normally.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the present invention will be described by way ofillustrative examples with reference to the accompanying drawings.

Example 1 (1) Information Recording Medium

FIG. 1 shows a data structure of an information recording medium 100according to a first example of the present invention.

The information recording medium (optical disc) 100 may be, for example,a rewritable optical disc. The optical disc 100 is assumed to besubjected to error correction in units of 1ECC block. An ECC block is aunit of error correction in the field of optical discs. An ECC blockhas, for example, a size of 32 kbytes in 16 sectors (each sector has asize of 2 kbytes). This size of one ECC block will be referred to as“1ECC size”, hereinafter. It is assumed that the recording ofinformation on the optical disc 100 and updating of the information onthe optical disc 100 are performed in units of 1ECC.

The data structure shown in FIG. 1 is the structure of the optical disc100 after position information on N number of defect areas in a defectmanagement area is normally recorded (N is an integer satisfying N≧0). Adefect area is, for example, a defect sector.

The optical disc 100 includes a data area 102 for recording user data,and a lead-in area 101 and a lead-out area 103 acting as a buffer areawhen a recording and reproduction apparatus (not shown) overruns by themovement of an optical head (not shown).

The data area 102 includes a user area 106 for recording user data and aspare area 107. When there is a defect area (for example, a defectsector) in the user area 106, the user data which is to be recorded inthe defect area is recorded in the spare area 107 instead of a portionof the user area 106 corresponding to the defect area.

The lead-in area 101 includes a first defect management area 104 and asecond defect management area 105 for recording defect managementinformation used for managing a defect area existing in the data area102.

The lead-out area 103 includes a third defect management area 108 and afourth defect management area 109 for recording defect managementinformation used for managing a defect area existing in the data area102, like the lead-in area 101.

The first defect management area 104, the second defect management area105, the third defect management area 108, and the fourth defectmanagement area 109 are respectively located at physically specificpositions on the optical disc 100.

In the first defect management area 104, the second defect managementarea 105, the third defect management area 108 and the fourth defectmanagement area 109, the same information for defect management isrecorded in multiplex. The reason for this is, as described above, thatthe information recorded in the first, second, third and fourth defectmanagement areas 104, 105, 108, and 109 cannot be a target of defectmanagement. Even if some of the first, second, third and fourth defectmanagement areas 104, 105, 108, and 109 have a defect area and theinformation recorded in the defect area cannot be reproduced, as long asat least one of the four defect management areas is defect-free, thedefect management information recorded in that area can be normallyreproduced. Accordingly, loss of the user data is prevented, whichimproves reliability. In the first example, the optical disc 100includes the four defect management areas 104, 105, 108, and 109, butthe number of defect management areas may be any number of one or more.

In the first defect management area 104, a disc definition structure 111and a defect list 112 for managing N number of defect areas existing inthe data area 102 (N is an integer satisfying N≧0) are recorded. Thefirst defect management area 104 includes an unused area 113.

The disc definition structure 111 is information representing the discstructure, for example, whether or not the disc 100 has been subjectedto defect management. This information also includes informationregarding the spare area 107. The disc definition structure 111 islocated at a physically specific position in the first defect managementarea 104. The disc definition structure 111 has a prescribed size.

In the unused area 113, currently meaningless information is recorded.Generally, padding data 127 (for example, 0) is recorded in the unusedarea 113. When a new defect area is detected in the user area 106, adefect entry for managing the new defect area is added to the defectlist 112. As a result, the size of the unused area 113 is decreased bythe size of the added defect entry.

The defect list 112 includes a header 121, a first defect entry 122, asecond defect entry 123, . . . , an (N−1)th defect entry 124, an Nthentry 125, and an anchor 126. The header 121, the first through Nthentries 122 through 125, and the anchor 126 are located in this order inthe defect list 112.

In the first example, it is assumed that the total of the size of thedefect list 112 and the size of the unused area 113 is 4ECC. The totalsize is not limited to 4ECC and is arbitrary.

The header 121 includes a defect list identifier 131 which representsthat the area is the defect list 112, a defect entry number 132 whichrepresents the number of entries included in the defect list 112, andfirst update times information 133 which represents the number of timeswhich an updated defect list has been recorded in the first defectmanagement area 104. In FIG. 1, the defect entry number 132 is N (N isan integer satisfying N≧0), and the content of the first update timesinformation 133 is M (M is an integer satisfying M≧0). The defect listidentifier 131 may be located, for example, at the start of the header121 as shown in FIG. 1.

The header 121 is located at a physically specified position. In thefirst example, the header 121 is located at the start of the defect list112. The position of the header 121 in the defect list 112 is arbitraryas long as the header 121, the first through Nth defect entries 122through 125, and the anchor 126 are located in this order in the defectlist 112.

In the case of the optical disc 100 shown in FIG. 1, the defect entrynumber 132 is N. Thus, the defect list 112 includes the first defectentry 122, . . . , and the Nth defect entry 125. The first defect entry122 includes first defect position information 141 which is positioninformation showing the position of a defect area, and first substituteposition information 142 which is position information showing theposition of a part of the spare area 107 which is usable instead of thedefect area. Likewise, the second defect entry 123 includes seconddefect position information and second substitute position information.The (N−1)th defect entry 124 and the Nth defect entry 125 also havesubstantially the same structure. Here, each of the first defectposition information 141 and the first substitute position information142 is generally a sector number.

The defect entries are generally located such that the defect positioninformation included therein is in an ascending order. Morespecifically, when, for example, the defect position information is asector number, defect position information having the smaller sectornumber is located in the first defect entry 122 as the first defectposition information 141. After this, the defect entries are located inthe order of the sector numbers. Defect position information having thelarger sector number is located in the Nth defect entry 125 as Nthdefect position information.

The defect entries in the defect list 112 do not need to be located inan ascending order. For example, the defect entries may be located suchthat the sector numbers are in a descending order. Alternatively, thedefect entries may be located randomly.

The anchor 126 includes an anchor identifier 151 for identifying thatthe area is an anchor of the defect list 112, second update timesinformation 152 which represents the number of times which the updateddefect list has been recorded in the first defect management area 104,and reserve information 153 for future expansion. In FIG. 1, the contentof the second update times information 152 is M (M is an integersatisfying M≧0), and is the same as that of the first update timesinformation 133. As long as the first defect management area 104 isupdated normally, the content of the first update times information 133and the content of the second update times information 152 are identicalto each other. The anchor identifier 151 may be located, for example, atthe start of the anchor 126 as shown in FIG. 1.

In this specification, the first and second update times information 133and 152 represent the number of times which the updated defect list hasbeen recorded in the first defect management area 104 (i.e., the numberof times which the defect list 112 has been updated and recorded on theoptical disc 100). The first and second update times information 133 and152 may represent the number of times which the defect list has beenupdated (i.e., the number of times which the defect list has beenupdated in the storage section described below). In the followingdescription, the first and second update times information 133 and 152represent the number of times which the updated defect list has beenrecorded in the first defect management area 104.

The anchor 126 is located subsequently to the Nth defect entry 125. Itshould be noted that since the size of the defect list 112 is variable,the position at which the anchor 126 is located is also variable.

Next, the header 121, the first defect entry 122, the anchor 126 and theunused area 113 will be described in detail.

FIGS. 2A through 2D respectively show detailed data structures of theheader 121, the first defect entry 122, the anchor 126 and the unusedarea 113.

In FIGS. 2A through 2D, “BP” represents the bit position, and “Val”represents the binary value corresponding to each BP. In the exampleshown in FIGS. 2A through 2D, the size of each of the header 121, thefirst defect entry 122, the anchor 126 and the unused area 113 is 8bytes (bit position 0 through bit position 63).

FIG. 2A shows an exemplary detailed structure of the header 121. In thisexample, Val for only the bit position 62 of the defect list identifier131 is 1 (Val=1); i.e., 0x4000 in hexadecimal representation.

FIG. 2B shows an exemplary detailed structure of the first defect entry122. It is assumed that the maximum number of the sector among thesectors usable in the data area 102 is 0x07FFFFFF in hexadecimalrepresentation. The maximum value which has a possibility of beingregistered as the first defect position information 141 in the firstdefect entry 122 is 0x07FFFFFF in hexadecimal representation as shown inFIG. 2B.

FIG. 2C shows an exemplary detailed structure of the anchor 126. In thisexample, Val for all the bit positions 59 through 63 in the anchoridentifier 151 is 1 (Val=1) i.e., 0xFFFF in hexadecimal representation.

FIG. 2D shows an exemplary detailed structure of the unused area 113. Inthe unused area 113, the padding data 127 is generally recorded. In theunused area 113, Val=0. In FIG. 2D, 0 is recorded as the padding data,but the padding data is not limited to 0.

For the defect list identifier 131 and the anchor identifier 151, avalue which is distinguishable from any other defect entry and that ofthe unused area 113 is adopted. As shown in FIG. 2C, Val=1 is set for atleast one of the bit positions 59 through 63 which are never 1 in anydefect entry or the unused area 113.

Similarly, as shown in FIG. 2A, Val=1 is set for at least one of the bitpositions 59 through 63 which are never 1 in any defect entry or theunused area 113, such that the value sequence of the bit positions 59through 63 in the defect list identifier 131 is different from that ofthe bit positions 59 through 63 in the anchor identifier 151.

Owing to such settings, the anchor identifier 151 is distinguishablefrom the defect list identifier 131, any defect entry, and the unusedarea 113. The defect list identifier 131 is also distinguishable fromthe anchor identifier 151, any defect entry, and the unused area 113.

The values for the defect list identifier 131 and the anchor identifier151 in FIGS. 2A and 2C are mere examples, and the values are not limitedto these.

In the first example, the defect list identifier 131 and the anchoridentifier 151 are distinguished from any defect entry and the unusedarea 113 and further the defect list identifier 131 and the anchoridentifier 151 are distinguishable from each other as described above.Therefore, even when any defect entry is read as the anchor identifier151 in the anchor 126, that defect entry is never erroneously determinedas the anchor identifier 151. Accordingly, it can be easily determinedwhether or not the defect list 112 has been updated normally.

Since it is not necessary to provide a header for each 1ECC size, theprocessing efficiency of updating the defect list is improved. Since theheader is not interposed between two defect entries, defect entries canbe easily searched for, added, and deleted.

The following description will be made with the premise that the opticaldisc 100 has the data structure shown in FIG. 1.

(2) Reproduction/Recording (Update)

FIG. 3 is a block diagram of a recording and reproduction apparatus 300according to the first example. The recording and reproduction apparatus300 records information on the optical disc 100 and/or reproducesinformation recorded on the optical disc 100.

The recording and reproduction apparatus 300 includes a control section301, a recording and reproduction section 302, and a storage section303.

The control section 301 controls the operation of the recording andreproduction section 302. The control section 301 may be, for example, aCPU. The control section 301 has an inherent defect list identifier foridentifying the defect list 112 of the optical disc 100 and an inherentanchor identifier for identifying the anchor 126 of the defect list 112of the optical disc 100, which are stored initially. The contents(values) of the inherent defect list identifier and the inherent anchoridentifier are correct and are not rewritable. The control section 301uses the recording and reproduction section 302 and the storage section303 to control the execution of the following processing: (a) defectmanagement processing for specifying the latest defect list among thedefect lists which are recorded in the first through fourth defectmanagement areas 104, 105, 108 and 109; and (b) defect managementprocessing for updating the defect lists which are recorded in the firstthrough fourth defect management areas 104, 105, 108 and 109 into thelatest defect list.

The recording and reproduction section 302 records information on theoptical disc 100 and/or reproduces the information recorded on theoptical disc 100. Such recording/reproduction is performed by, forexample, emitting laser so as to write the information on the opticaldisc 100 as a signal and/or so as to read the information written as asignal on the optical disc 100.

The storage section 303 stores information to be recorded on the opticaldisc 100 and/or stores information which has been reproduced from theoptical disc 100. The storage section 303 may be, for example, a randomaccess memory (RAM). Owing to the operation of the control section 301,the storage section 303 includes a defect list area saved for storingthe defect list 112 reproduced from a defect management area (forexample, the first defect management area 104) of the optical disc 100or a latest defect list to be recorded in the defect management area.

(2-1) Defect Management Processing for Specifying the Latest Defect List

Next, the operation of defect management processing for specifying thelatest defect list performed by the recording and reproduction apparatus300 will be described.

The control section 301 executes the defect management processing. Thecontrol section 301 follows the procedure of the defect managementprocessing to request the recording and reproduction section 302 toreproduce the information of the disc definition structure 111 locatedat the start of the first defect management area 104 and store thereproduced information from the disc definition structure 111 in thestorage section 303.

Upon the request from the control section 301, the recording andreproduction section 302 reproduces the information of the discdefinition structure 111 from the optical disc 100 and stores theinformation in the storage section 303. The recording and reproductionsection 302 reports to the control section 301 that the reproduction andstorage of the information of the disc definition structure 111 has beencompleted.

Upon receiving the report from the recording and reproduction section302, the control section 301 checks whether or not the optical disc 100has been subjected to defect management, based on the information of thedisc definition structure 111 stored in the storage section 303.

When confirming that the optical disc 100 has been subjected to defectmanagement, the control section 301 requests the recording andreproduction section 302 to reproduce the header 121 located at a fixedposition of the defect list 112 (in the example of FIG. 1, at the startof the defect list 112) recorded in the first defect management area 104and to store the reproduced header 121 in the storage section 303.

Upon the request from the control section 301, the recording andreproduction section 302 reproduces the header 121 located at the startof the defect list 112 recorded in the first defect management area 104and store the reproduced header 121 in the storage section 303. Therecording and reproduction section 302 reports to the control section301 that the reproduction and storage of the header 121 has beencompleted.

Upon receiving the report from the recording and reproduction section302, the control section 301 compares the content of the inherent defectlist identifier initially stored in the control section 301 with thecontent of the defect list identifier 131 included in the header 121stored in the storage section 303 to check whether or not the storedinformation is the header 121 in the defect list 112.

When the two contents compared match each other, the control section 301determines that the stored information is the header 121 in the defectlist 112 and proceeds with the defect management processing. When thetwo contents compared do not match each other, the control section 301determines that updating of the first defect management area 104 failed(abnormal defect management area) and terminates the defect managementprocessing. The two contents compared do not match each other when, forexample, there is a defect area in the first defect management area 104and thus information cannot be read therefrom.

In order to identify the anchor 126 in the defect list 112 recorded inthe first defect management area 104, the control section 301 uses thedefect entry number 132 included in the header 121 stored in the storagesection 303 to calculate the position of the start of the anchor 126 inthe defect list 112. The position of the start of the anchor 126 can beobtained by multiplying the defect entry number 132 by the size of onedefect entry which is a fixed value.

The control section 301 requests the recording and reproduction section302 to reproduce the anchor 126 in the defect list 112 based on thecalculated position, and store the reproduced information in the storagesection 303.

Upon the request from the control section 301, the recording andreproduction section 302 reproduces the information present at thedesignated position in the defect list 112 and stores the reproducedinformation in the storage section 303. The recording and reproductionsection 302 reports to the control section 301 that the reproduction andstorage of the information present at the designated position has beencompleted.

Upon receipt of the report from the recording and reproduction section302, the control section 301 compares the content of the inherent anchoridentifier initially stored in the control section 301 with the contentof the information located at the start of the entire information storedin the storage section 303 to check whether or not the storedinformation is the anchor 126 in the defect list 112. The “informationlocated at the start of the entire information stored in the storagesection 303” is the information expected to be the anchor identifier 151included in the anchor 126.

When the two contents compared match each other, the control section 301determines that the stored information is the anchor 126 in the defectlist 112 and proceeds with the defect management processing. When thetwo contents compared do not match each other, the control section 301determines that updating of the first defect management area 104 failed(abnormal defect management area) and terminates the defect managementprocessing. The two contents compared do not match each other when, forexample, the information present at the position calculated using thedefect entry number 132 is not the anchor 126. More specifically, thetwo contents compared do not match each other when, for example, therecording and reproduction apparatus 300 is turned off while the firstthrough Nth defect entries 122 through 125 in the defect list 112 arebeing updated. In this case, the defect entry number 132 included in theheader 121 does not match the total number of the first through Nthdefect entries 122 through 125.

The control section 301 compares the content of the first update timesinformation 133 included in the header 121 with the second update timesinformation 152 included in the anchor 126 stored in the storage section303.

When the two contents compared match each other, the control section 301determines that the first defect management area 104 has been updatednormally, and proceeds with the defect management processing.

When the two contents compared do not match each other, the controlsection 301 determines that updating of the first defect management area104 failed (abnormal defect management area) and terminates the defectmanagement processing. The two contents compared do not match each otherwhen, for example, the recording and reproduction apparatus 300 isturned off while the first through Nth defect entries 122 through 125 inthe defect list 112 are being updated and therefore updating of thedefect entries 122 through 125 is not completed. In this case, thecontent of the first update times information 133 included in the header121 does not match the content of the second update times information152 included in the anchor 126.

The control section 301 performs substantially the same processing foreach of the second defect management area 105, the third defectmanagement area 108 and the fourth defect management area 109.

After checking whether or not each of the first through fourth defectmanagement areas 104, 105, 108 and 109 is a normal defect managementarea, the control section 301 specifies the latest defect managementarea among the defect management areas which have been determined to benormal, as follows. The control section 301 makes a comparison of thefirst update times information 133 recorded in the defect managementareas which have been determined to be normal, and specifies the defectmanagement area having the largest number of updates as the latestdefect management area. The defect list recorded in the specified latestdefect management area is specified as the latest defect list.

For specifying the latest defect management area, the second updatetimes information 152 included in the anchor 126 may be used instead ofthe first update times information 133.

The control section 301 requests the recording and reproduction section302 to reproduce the defect list recorded in the specified latest defectmanagement area and store the reproduced defect list in the defect listarea saved in the storage section 303.

Upon the request from the control section 301, the recording andreproduction section 302 reproduces the defect list recorded in thespecified latest defect management area and stores the reproduced defectlist in the defect list area in the storage section 303. The recordingand reproduction section 302 reports to the control section 301 that thereproduction and storage of the defect list has been completed.

Thus, the operation of defect management processing for specifying thelatest defect list performed by the recording and reproduction apparatus300 is completed.

Using the specified latest defect list, the user data recorded in thedata area 102, for example, can be reproduced. In this case, the controlsection 301 requests the recording and reproduction section 302 toreproduce the user data based on the latest defect list and store thereproduced user data in the storage section 303.

Upon the request from the control section 301, the recording andreproduction section 302 reproduces the user data from the data area 102and stores the reproduced user data in the storage section 303.

Information recording may be performed using the specified latest defectlist.

FIG. 4 shows a procedure of defect management processing for specifyingthe latest defect list in the first example. The defect managementprocessing is executed by the control section 301. Hereinafter, eachstep of the procedure of defect management processing will be described.The procedure of defect management processing is started after it isconfirmed that the optical disc 100 has been subjected to defectmanagement. Whether or not the optical disc 100 has been subjected todefect management is determined based on the disc definition structure111 in the optical disc 100.

Step S401: The defect list identifier 131, the defect entry number 132and the first update times information 133 included in the header 121are reproduced. The content of the reproduced defect list identifier 131is compared with the content of the inherent defect list identifier. Theinherent defect list identifier identifies the defect list 112 in theoptical disc 100. The inherent defect list identifier has a correctvalue which is not rewritable. The inherent defect list identifier maybe initially stored in the control section 301. When the two contentscompared match each other, the defect management processing advances tostep S402. When the two contents compared do not match each other, thedefect management processing advances to step S406.

Step S402: When the content of the defect list identifier 131 and thecontent of the inherent defect list identifier are determined to matcheach other in step S401, the reproduced information is determined to bethe header 121 in the defect list 112. Using the defect entry number 132included in the header 121, the position of the start of the anchor 126in the defect list 112 is calculated. The position of the start of theanchor 126 is obtained by multiplying the defect entry number 132 by thesize of one defect entry which is a fixed value. The defect managementprocessing advances to step S403.

Step S403: Based on the position obtained in step S402, informationexpected to be the anchor identifier 151 and the second update timesinformation 152 included in the anchor 126 are reproduced. The contentof the information expected to be the anchor identifier 151 is comparedwith the content of the inherent anchor identifier. The inherent anchoridentifier identifies the anchor of the defect list 112. The inherentanchor identifier has a correct value which is not rewritable. Theinherent anchor identifier is initially stored in the control section301. When the two contents compared are determined to match each other,the defect management processing advances to step S404. When the twocontents compared are determined not to match each other, the defectmanagement processing advances to step S406.

Step S404: When the content of the information expected to be the anchoridentifier 151 and the content of the inherent anchor identifier aredetermined to match each other in step S403, the stored information isdetermined to be the anchor 126 in the defect list 112. The content ofthe first update times information 133 included in the header 121 iscompared with the content of the second update times information 152included in the anchor 126. When the two contents compared aredetermined to match each other, the defect management processingadvances to step S405. When the two contents compared are determined notto match each other, the defect management processing advances to stepS406.

Step S405: When the content of the first update times information 133and the content of the second update times information 152 aredetermined to match each other in step S404, the first defect managementarea 104 is determined to have been updated normally. Then, the defectmanagement processing advances to step S407.

Step S406: When the contents compared are determined not to match eachother in steps S401, S403 or S404, updating of the first defectmanagement area 104 is determined to have failed (abnormal defectmanagement area), and the defect management processing for the firstdefect management area 104 is terminated. The defect managementprocessing advances to step S407.

Step S407: It is determined whether or not the operations in steps S401through S406 have been performed for all the defect management areas inthe optical disc 100. When the operations in steps S401 through S406have not been performed for all the defect management areas, the defectmanagement processing returns to step S401. When the operations in stepsS401 through S406 have been performed for all the defect managementareas, the defect management processing advances to step S408.

Step S408: The latest defect list is specified. More specifically, thelatest defect management area among the defect management areasdetermined to be normal is specified, as follows. A comparison is madeof the first update times information (or the second update timesinformation) recorded in the defect management areas determined to benormal, and the defect management area having the largest number ofupdates is specified as the latest defect management area. The defectlist recorded in the specified latest defect management area isspecified as the latest defect list.

When the latest defect list of the optical disc 100 is specified bysteps S401 through S408, the defect management processing is completed.Using the latest defect list obtained in step S408, the user datarecorded in the data area 102, for example, can be reproduced.

(2-2) Defect Management Processing for Updating the Latest Defect List

Returning to FIG. 3, the operation of defect management processing forupdating the latest defect list performed by the recording andreproduction apparatus 300 will be described. In the following example,the defect list is updated when another defect area is detected whilethe user data is being recorded in the data area 102 of the optical disc100, or when a portion of the user area 106 which was previouslydetermined to be a defect area is determined to be a normal defect areawhile the user data recorded in the data area 102 is being reproduced.Throughout this specification, a “normal defect area” is defined to meanan area which was previously determined to be a defect area butcurrently has no defect and allows information to be recorded thereinand/or allows information therein to be reproduced. An area which waspreviously determined to be a defect area is currently determined to bea normal defect area when, for example, the defect is caused by dust orstain such as a fingerprint on the surface of the optical disc. In thiscase, when the user cleans the surface of the optical disc to remove thedust or stain, the area in which the dust or stain existed (i.e., thearea which was previously determined to be a defect area) is currentlydetermined to be a normal area usable for recording/reproduction.

The storage section 303 stores the latest defect list. The latest defectlist may be located in the defect list area in the storage section 303.The latest defect list includes the latest header, P number of latestdefect entries (P is an integer satisfying P≧0 where P=N or P≠N), andthe latest anchor. In the first example, the latest header, the P numberof latest defect entries, and the latest anchor are located in thelatest defect list in this order. The latest header is located at afixed position in the latest defect list. The latest anchor is locatedsubsequently to the Pth latest defect entry among the P number of latestdefect entries. The latest header includes the latest defect listidentifier, the first latest update times information and the latestdefect entry number P. The content of the latest defect list identifieris always the same as that of the inherent defect list identifier storedin the control section 301. The latest anchor includes the latest anchoridentifier and the second latest update times information which has thesame content as that of the first latest update times information. Thecontent of the latest anchor identifier is always the same as that ofthe inherent anchor list identifier stored in the control section 301.It is assumed that the P number of latest defect entries are arranged inan ascending order of the defect position information (defect sectornumbers). The latest defect list may include an unused area. It is notalways necessary that the latest header includes the latest defect listidentifier. Similarly, it is not always necessary that the latest anchorincludes the latest anchor identifier.

The above-described arrangement of the latest header and the P number oflatest defect entries and the latest anchor is merely an example. Thearrangement of the latest header and the P number of latest defectentries and the latest anchor in the latest defect list is arbitrary.

The control section 301 executes the defect management processing. Thecontrol section 301 requests the recording and reproduction section 302to determine whether (a) another defect area exists in the data area102, (b) a defect area which was previously determined to be a defectarea is currently a normal defect area, or (c) neither (a) nor (b) isthe case. Whether or not another defect area exists in the data area 102is determined by, for example, comparing a signal obtained byreproducing data immediately after user data is recorded with a signalrepresenting user data to be recorded. When these signals match eachother, the user data is determined to have been normally recorded in thedata area 102. When these signals do not match each other, it isdetermined that the user data has not been normally recorded in the dataarea 102 and another defect area exists in the data area 102.

When determining that another defect area exists in the data area 102 orthat the area which was previously determined to be a defect area iscurrently a normal defect area, the control section 301 updates thelatest defect list stored in the storage section 303.

Specific procedures of updating the latest defect list will bedescribed. There are three cases of updating the latest defect list,namely, (i) addition of a defect entry, (ii) deletion of a defect entry;and (iii) change of a defect entry. Each of these cases will bedescribed one by one.

(i) Addition of a Defect Entry

When it is determined that another defect area exists in the user area106, a defect entry including the position information on the positionof the another defect area is added to the latest defect list. Based onthe defect position information on the detected defect area, the controlsection 301 determines the position of the defect entry to be added. Thecontrol section 301 shifts the other defect entries and the latestanchor existing subsequent to the determined position toward the unusedarea, and adds the defect entry including the position information onthe another defect area at the determined position. As a result, the Pnumber of latest defect entries are updated to P′ number of latestdefect entries (P≠P′, P<P′).

Following the addition of the defect entry, the control section 301updates the latest defect entry number from P into P′. In this case, thelatest defect entry number is increased by the number of the addeddefect entries (i.e., by the number of the detected defect sectors).

After the P number of latest defect entries and the latest defect entrynumber P are updated, the control section 301 increments, by one, thecontent of the first latest update times information included in thelatest header and the content of the second latest update timesinformation included in the latest anchor.

(ii) Deletion of a Defect Entry

When an area which was previously determined to be a defect area iscurrently determined to be a normal defect area, the control section 301deletes the defect entry including the position information on the areadetermined to be the normal defect area. The control section 301 thenshifts the defect entries located subsequent to the deleted defect entryand the latest anchor toward the latest header by the size of thedeleted defect entry. The unused area is expanded by the size of thedeleted defect entry, and the control section 301 records padding data(for example, 0) in the expanded portion of the unused area. As aresult, the P number of latest defect entries are updated to P′ numberof latest defect entries (P≠P′, P>P′).

Following the deletion of the defect entry, the control section 301updates the latest defect entry number from Pinto P′. In this case, thelatest defect entry number is decreased by the number of the deleteddefect entries (i.e., by the number of the defect sectors determined tobe normal).

After the P number of latest defect entries and the latest defect entrynumber P are updated, the control section 301 increments, by one, thecontent of the first latest update times information included in thelatest header and the content of the second latest update timesinformation included in the latest anchor.

(iii) Change of a Defect Entry

When another defect area is determined to exist in the spare area 107,the control section 301 rewrites the substitute position informationcorresponding to the another defect area in the latest defect list. Thesubstitute position information corresponding to the another defect areais rewritten into substitute position information representing a portionother than the another defect area in the spare area 107.

The control section 301 changes the latest defect entry number from P toP′ (P=P′ since no defect entry is added to or deleted from the latestdefect list). Although the number of the latest defect entries remainsthe same, the substitute position information included is different.Throughout this specification, “updating of a defect list” encompassesthe case of not changing the number of defect entries included in thedefect list in addition to the case of changing the number of defectentries included in the defect list.

After the P number of latest defect entries and the latest defect entrynumber P are updated, the control section 301 increments, by one, thecontent of the first latest update times information included in thelatest header and the content of the second latest update timesinformation included in the latest anchor.

The operations (i) through (iii) are performed by the control section301 for the latest defect list stored in the storage section 303. In thecase where the first and second update times information 133 and 152represent the number of times which the updated latest defect list hasbeen recorded in the first defect management area 104, the first andsecond latest update times information may each be incremented by oneonly once before the updated latest defect list is recorded in the firstdefect management area 104. By contrast, in the case where the first andsecond update times information 133 and 152 represent the number oftimes which the latest defect list has been updated in the storagesection 303, the first and second latest update times information may beincremented by one each time the latest defect entries and the latestdefect entry number are updated.

The control section 301 requests the recording and reproduction section302 to record the latest defect list updated in the storage section 303in the first defect management area 104 of the optical disc 100. Forexample, the control section 301 requests the recording and reproductionsection 302 to record the updated latest header, the updated P′ numberof latest defect entries, and the updated latest anchor in the firstdefect management area 104 in this order.

Upon the request from the control section 301, the recording andreproduction section 302 records the updated latest defect list in thefirst defect management area 104. The updated defect list replacing thedefect list 112 is recorded in the first defect management area 104 inthe order of the latest header replacing the header 121, the latestdefect entries replacing the first through Nth defect entries 122through 125, and the latest anchor replacing the anchor 126. Therecording and reproduction section 302 reports to the control section301 that the recording of the updated latest defect list in the firstdefect management area 104 has been completed.

The control section 301 requests the recording and reproduction section302 to record the latest defect list updated in the storage section 303in each of the second through fourth defect management areas 105, 108and 109. More specifically, again, the control section 301 requests therecording and reproduction section 302 to record the updated latestheader, the updated latest defect entries, and the updated latest anchorin this order in the second through fourth defect management areas 105,108 and 109.

Upon the request from the control section 301, the recording andreproduction section 302 records the updated latest defect list in eachof the second through fourth defect management areas 105, 108 and 109.

Thus, the operation of defect management processing for updating thelatest defect list performed by the recording and reproduction apparatus300 is completed.

The order of recording the updated latest defect list is not limited tothe above-described order of the latest header, the P′ number of latestdefect entries, and the latest anchor. As long as the header 121, the Nnumber of defect entries 122 through 125, and the anchor 126 are locatedin this order in the defect list 112, the control section 301 mayrequest the recording and reproduction section 302 to record the updatedlatest anchor, the updated P′ number of latest defect entries, and theupdated latest header in this order in each of the first through fourthdefect management areas 104, 105, 108 and 109, and the recording andreproduction section 302 may record the updated latest defect list ineach of the first through fourth defect management areas 104, 105, 108and 109 upon the request from the control section 301.

FIG. 5 shows a procedure of defect management processing for updatingthe latest defect list in the first example. The defect managementprocessing is executed by the control section 301. Hereinafter, eachstep of the procedure of defect management processing will be described.

Step S501: It is determined whether (a) another defect area exists inthe data area 102, (b) a defect area which was previously determined tobe a defect area is currently a normal defect area, or (c) neither (a)nor (b) is the case. When it is determined that (a) another defect areaexists in the data area 102 or that (b) the defect area is currently anormal defect area, the defect management processing advances to stepS502. When it is determined that neither (a) nor (b) is the case, thedefect management processing is terminated. Such a determination is, forexample, performed when recording user data in the data area 102 orreproducing user data recorded in the data area 102.

Step S502: The latest defect entries and the latest defect entry numberP are updated. The P number of latest defect entries are updated to P′number of latest defect entries. The latest defect entry number P isupdated to P′.

More specifically, when another defect area is determined to exist inthe user area 106, another defect entry is added to the latest defectlist. Next, the latest defect entry number is increased by the number ofthe added defect entries (P≠P′, P<P′).

When another defect is determined to exist in the spare area 107, thesubstitute position information corresponding to the another defect areain the latest defect list is rewritten. The substitute positioninformation corresponding to the another defect area is rewritten intosubstitute position information representing a portion other than theanother defect area in the spare area 107. The latest defect entrynumber is not changed (P=P′).

When an area which was previously determined to be a defect area iscurrently determined to be a normal defect area, the defect entryincluding the position information on the position of the defect areawhich was previously determined to be a defect area is deleted. Next,the latest defect entry number is decreased by the number of the deleteddefect entries (i.e., the number of defect areas (number of sectors)currently determined to be normal) (P≠P′, P>P′).

When the latest defect entries and the latest defect entry number Pareupdated, the defect management processing advances to step S503.

Step S503: The first and second latest update times information are eachincremented by one. Then, the defect management processing advances tostep S504.

Step S504: The latest defect list updated in steps S502 and S503 isrecorded in the first defect management area 104 of the optical disc100. For example, the updated latest header, the updated P′ number oflatest defect entries, and the updated latest anchor are recorded in thefirst defect management area 104 in this order. Then, the defectmanagement processing advances to step S505. As long as the header 121,the N number of defect entries 122 through 125, and the anchor 126 arelocated in this order in the defect list 112, the updated latest anchor,the updated P′ number of latest defect entries, and the updated latestheader may be recorded in this order in the first defect management area104.

Step S505: It is determined whether or not the updated defect list hasbeen recorded in all the defect management areas of the optical disc 100(in this case, the first through fourth defect management areas 104,105, 108 and 109). When the updated defect list has been recorded in allthe defect management areas of the optical disc 100, the defectmanagement processing is terminated. When the updated defect list hasnot been recorded in all the defect management areas of the optical disc100, the defect management processing returns to step S504.

As described above, the arrangement of the latest header, the P′ numberof latest defect entries and the latest anchor in the latest defect listis arbitrary. The updated latest defect list is recorded in each of thefirst through fourth defect management areas 104, 105, 108 and 109 ofthe optical disc 100 as follows. Such that the updated latest header islocated at the position of the header 121, the updated P′ number oflatest defect entries are located at the positions of the defect entries122 through 125, and the updated latest anchor is located at theposition of the anchor 126, the updated latest defect list is recordedin each of the first through fourth defect management areas 104, 105,108 and 109 in the order of the updated latest header, the updated P′number of latest defect entries, and the updated latest anchor or in theorder of the updated latest anchor, the updated P′ number of latestdefect entries, and the updated latest header.

In the above description, the updated latest defect list is recorded onthe optical disc 100 shown in FIG. 1 where the optical disc 100 has beensubjected to defect management. Next, recording of the updated latestdefect list on an optical disc in an initial state immediately afterbeing shipped from the plant will be described.

An optical disc in an initial state is assumed to have the samestructure as that shown in FIG. 1 except that, for example, the defectlist 112 (FIG. 1) has no information. In such optical disc, neither adefect list identifier for identifying the defect list nor an anchoridentifier for identifying the anchor of the defect list is recorded.Therefore, in the case where the latest defect list includes neither thelatest defect list identifier nor the latest anchor identifier, thedefect management processing of recording the latest defect listincludes the process of recording the defect list identifier and theanchor identifier in addition to the process of recording the latestdefect list in the defect management area. In the case where the latestdefect list includes the latest defect list identifier and the latestanchor identifier, no detailed explanation will be given since theprocessing was described above with reference to FIG. 5.

The control section 301 requests the recording and reproduction section302 to record the latest defect list stored in the storage section 303in the defect management area of the optical disc and to record theinherent defect list identifier and the inherent anchor identifier,which are initially stored in the control section 301, in a defectmanagement area of the optical disc. More specifically, the inherentdefect list identifier is recorded in the defect management area so asto be located at the start of the header 121. The inherent anchoridentifier is recorded in the defect management area so as to be locatedat the start of the anchor 126. In this case, an arbitrary value isrecorded as the latest defect entry number and as the latest defectentry of the latest defect list which respectively correspond to thedefect entry number 132 and the first through Nth defect entries 122through 125. As the first update times information and as the secondupdate times information, for example, 0 or 1 is recorded. The values tobe recorded as the first and second update times information arearbitrary as long as the values are equal to each other and representthat recording has been performed on an optical disc in the initialstate only once.

The method for recording the defect list identifier and the anchoridentifier in the defect management area is not limited to theabove-described method. For example, the inherent defect list identifieralready stored in the control section 301 is given as the latest defectlist identifier at the start of the latest header of the latest defectlist stored in the storage section 303. Similarly, the inherent anchoridentifier already stored in the control section 301 is given as thelatest anchor identifier at the start of the latest anchor of the latestdefect list. As the defect management processing performed on an opticaldisc in the initial state, the latest defect list including the latestdefect list identifier and the latest anchor identifier obtained in thismanner may be recorded in the defect management area.

This process of defect management processing is performed in steps S504and S505 in FIG. 5.

In the first example, it is accurately determined whether or not thedefect management area has been updated normally. This will be describedin three different cases of update. In the following explanation, theoptical disc 100 is used.

Specific Example 1 When a Defect Entry is Added

FIG. 6 shows data structures of a defect list in various states. Part(a) shows a data structure of a pre-update defect list. Part (b) shows adata structure of a defect list which was updated normally. Part (c)shows a data structure of a defect list which was not updated normally.

FIG. 6 shows the case where another defect area (defect sector) isdetected in the user area 106 and one defect entry is added. Theaddition of the defect entry is performed as described above withreference to FIGS. 3 and 5.

Part (a) of FIG. 6 shows a data structure before the defect list isupdated. The defect list shown in part (a) is the same as the defectlist 112 shown in FIG. 1. The defect list includes a first defect entry,. . . , and an Nth defect entry. The defect entry number is N, and thecontent of each of the first update times information and the secondupdate times information is M.

Part (b) of FIG. 6 shows a data structure after the defect list isupdated normally (one defect entry is added normally). When one defectentry is added normally to the defect list, the defect list includes thefirst defect entry, . . . , the Nth defect entry, and an (N+1)th defectentry. The number of defect entries is increased by one from the statein part (a) of FIG. 6. The defect entry number is updated from N to N+1.The content of each of the first update times information and the secondupdate times information is updated from M to M+1.

Following the addition of the defect entry, the position of the anchoris shifted toward the unused area by the size of the added defect entryfrom the position shown in part (a) of FIG. 6. The shifted position ofthe anchor is calculated as follows. The defect entry number (N+1)included in the header is multiplied by the size of one defect entry.The shifted position of the anchor is away toward the unused area fromthe end of the header by the multiplication result. At this point, theinformation which is read from the calculated position matches the valueof the inherent anchor identifier of the control section 301. Thus, itis confirmed that the anchor is read. In addition, the content of thefirst updated times information matches the content of the secondupdated times information. Thus, it can be determined that the defectlist has been updated normally.

Part (c) of FIG. 6 shows a data structure of a defect data in the casewhere the update failed before the anchor is recorded. The failureoccurs when, for example, the recording and reproduction apparatus 300is turned off while the defect list is being updated. In part (c) ofFIG. 6, the defect list includes the first defect entry, . . . , and theNth defect entry, like in part (a) of FIG. 6. Although the defect listincludes the same defect entries as those of part (a) of FIG. 6, thedefect entry number is updated from N to (N+1). The content of the firstupdate times information is updated from M to (M+1). However, thecontent of the second update times information is M like in part (a) ofFIG. 6. In this case, the anchor is not located at the position which isobtained by multiplying the defect entry number (N+1) included in theheader by the size of one defect entry. The information which is readfrom the position calculated as the position of the anchor is paddingdata (=0 in part (c) of FIG. 6) which is recorded in the unused area andis meaningless information. The information which is read as theposition of the anchor is different from the value of the inherentanchor identifier of the control section 301. Thus, it is determinedthat the updating of the defect list failed.

Specific Example 2 When a Defect Entry is Deleted

FIG. 7 shows data structures of a defect list in various states. Part(a) shows a data structure of a pre-update defect list. Part (b) shows adata structure of a defect list which was updated normally. Part (c)shows a data structure of a defect list which was not updated normally.

FIG. 7 shows the case where a defect area which was previouslydetermined to be a defect area is currently determined to be a normaldefect area, and the defect entry including the position information onthe position of the defect area which is currently determined to be thenormal defect area is deleted. The deletion of the defect entry isperformed as described above with reference to FIGS. 3 and 5.

Part (a) of FIG. 7 shows a data structure before the defect list isupdated. The defect list shown in part (a) is the same as the defectlist 112 shown in FIG. 1.

Part (b) of FIG. 7 shows a data structure after the defect entry isdeleted normally. When one defect entry is deleted normally from thedefect list, the defect list includes the first defect entry, . . . ,and an (N−1)th defect entry. The number of defect entries is decreasedby one from the state in part (a) of FIG. 7. The defect entry number isupdated from N to N−1. The content of each of the first update timesinformation and the second update times information is updated from M toM+1.

Following the deletion of the defect entry, the position of the anchoris shifted toward the header by the size of the deleted defect entryfrom the position shown in part (a) of FIG. 7. The shifted position ofthe anchor is calculated as follows. The defect entry number (N−1)included in the header is multiplied by the size of one defect entrylike in Specific example 1. The shifted position of the anchor is awaytoward the unused area from the end of the header by the multiplicationresult. At this point, the information which is read from the calculatedposition matches the value of the inherent anchor identifier of thecontrol section 301. Thus, it is confirmed that the anchor is read. Inaddition, the content of the first updated times information matches thecontent of the second updated times information. Thus, it can bedetermined that the defect list has been updated normally.

Part (c) of FIG. 7 shows a data structure of a defect data in the casewhere the update failed before the anchor is recorded. The failureoccurs when, for example, the recording and reproduction apparatus 300is turned off while the defect list is being updated. In part (c) ofFIG. 7, the defect list includes the first defect entry, . . . , and theNth defect entry, like in part (a) of FIG. 7. Although the defect listincludes the same defect entries as those of part (a) of FIG. 7, thedefect entry number is updated from N to (N−1). The content of the firstupdate times information is updated from M to (M+1). However, thecontent of the second update times information is M like in part (a) ofFIG. 7. In this case, the anchor is not located at the position which isobtained by multiplying the defect entry number (N−1) included in theheader by the size of one defect entry. The information which is readfrom the position calculated as the position of the anchor is the Nthdefect position information which is included in the Nth defect entry.The value of the inherent anchor identifier of the control section 301is different from any of the defect list identifier, the defect entries,or the padding data as described above with reference to FIGS. 2Athrough 2D. Thus, it never occurs that the content of the Nth defectposition information accidentally matches the value of the inherentanchor identifier, resulting in an erroneous determination that thedefect list has been updated normally.

Specific Example 3 When a Defect Entry is Changed

FIG. 8 shows data structures of a defect list in various states. Part(a) shows a data structure of a pre-update defect list. Part (b) shows adata structure of a defect list which was updated normally. Part (c)shows a data structure of a defect list which was not updated normally.

FIG. 8 shows the case where another defect area exists in the spare area107 which is used as the substitute area (substitute sector) for thedefect area (defect sector) represented by the (N−1)th defect positioninformation, and the substitute position information in the (N−1)thdefect entry is changed. The change of the defect entry is performed asdescribed above with reference to FIGS. 3 and 5.

Part (a) of FIG. 8 shows a data structure before the defect list isupdated. The defect list shown in part (a) is the same as the defectlist 112 shown in FIG. 1.

Part (b) of FIG. 8 shows a data structure after the defect list ischanged normally (after the substitute position information is changednormally). Since no defect entry is added or deleted, the defect listincludes the first defect entry, . . . , and the Nth defect entry likein part (a) of FIG. 8. The number of defect entries is N like in part(a) of FIG. 8. The content of each of the first update times informationand the second update times information is updated from M to M+1.

Accordingly, the position of the anchor after the update is the same asthe position of the anchor before the update. The position of the anchoris calculated as follows. The defect entry number N included in theheader is multiplied by the size of one defect entry. The position ofthe anchor is away toward the unused area from the end of the header bythe multiplication result. At this point, the information which is readfrom the calculated position matches the value of the inherent anchoridentifier of the control section 301. Thus, it is confirmed that theanchor is read. In addition, the content of the first updated timesinformation matches the content of the second updated times information.Thus, it can be determined that the defect list has been updatednormally.

Part (c) of FIG. 8 shows a data structure of a defect data in the casewhere the update failed before the anchor is recorded. The failureoccurs when, for example, the recording and reproduction apparatus 300is turned off while the defect list is being updated. In part (c) ofFIG. 8, the defect list includes the first defect entry, . . . , and theNth defect entry, like in part (a) of FIG. 8. The defect entry number isN like in part (a) of FIG. 8. The content of the first update timesinformation is updated from M to (M+1). However, the content of thesecond update times information is M like in part (a) of FIG. 8. In thiscase, the position which is obtained by multiplying the defect entrynumber N included in the header by the size of one defect entry is thecorrect position of the anchor. However, since the content of the firstupdate times information is different from the content of the secondupdate times information, it never occurs that the defect list iserroneously determined to have been updated normally.

In the first example, the header 121 includes the defect list identifier131. The header 121 is located at a physically specified position in theoptical disc 100 and therefore does not need to include the defect listidentifier 131. Even without the defect list identifier 131, the sameeffect as described in the first example can be provided.

As described above, according to the first example of the presentinvention, the information recording medium 100 includes the data area102 for recording user data, and the defect management areas 104, 105,108 and 109 for recording a defect list used for managing N number ofdefect areas existing in the data area 102 (N is an integer satisfyingN≧0). The defect list 112 includes the header 121, the N number ofdefect entries respectively including the position information on thepositions of the N number of defect areas, and the anchor 126. Theheader 121, the N number of defect areas, and the anchor 126 are locatedin this order in the defect list 112.

Owing to such a structure, the size of the defect list 112 is variable.Since the size of the defect list 112 is varied in accordance with thenumber of detected defect areas (defect sectors), the size of the defectlist 112 is decreased when the number of the defect areas is small.Namely, the defect list 112 is accommodated in a small ECC size (e.g.,1ECC size). When the size of the defect list 112 is small, the timerequired for recording the defect list 112 in the defect management areais shorter and the processing efficiency is improved. Even when a defectarea exists in the remaining ECC blocks (unused area) of the defectmanagement area other than the defect list 112, that defect managementarea can be processed as a normal defect management area. Accordingly,data in the defect management area can be normally reproduced.

According to the first example of the present invention, the header 121includes the defect list identifier 131 for identifying the defect list112, the first update times information 133 representing the number oftimes which the defect list 112 has been updated, and the defect entrynumber 132 representing the number of defect entries. The anchor 126includes the anchor identifier 151 for identifying the anchor of thedefect list 112, and the second update times information 152representing the number of times which the defect list 112 has beenupdated.

Owing to such a structure, it is not necessary to provide a header foreach 1ECC size even when the size of the defect list 112 is notaccommodated in 1ECC size. Thus, the processing efficiency of updatingthe defect list 112 is improved. Since the header is not interposedbetween the two defect entries, defect entries can be, for example,searched for, added and deleted easily.

The content of the anchor identifier 151 is different from any of thedefect list identifier 131, the defect entry number 132, the firstupdate times information 133, the defect entries, or the second updatetimes information 152. As such, even when a defect entry is deleted, theinformation which is erroneously read as the anchor identifier 151 nevermatches the content of the inherent anchor identifier. Therefore, thedefect list 112 is not erroneously determined to have been updatednormally when it has not been updated normally.

Example 2 (1) Information Recording Medium

FIG. 9 shows a data structure of an information recording medium 900according to a second example of the present invention.

The information recording medium (optical disc) 900 may be, for example,a rewritable optical disc. The optical disc 900 is assumed to besubjected to error correction in units of 1ECC block. An ECC block is aunit of error correction in the field of optical discs. This size of oneECC block will be referred to as “1ECC size”, hereinafter. It is assumedthat the recording of information on the optical disc 900 and updatingof the information on the optical disc 900 are performed in units of1ECC block.

The data structure shown in FIG. 9 is the structure of the optical disc900 after position information on N number of defect areas in a defectmanagement area is normally recorded (N is an integer satisfying N≧0). Adefect area is, for example, a defect sector.

The optical disc 900 includes a data area 902 for recording user data,and a lead-in area 901 and a lead-out area 903 acting as buffer areaswhen a recording and reproduction apparatus (not shown) overruns by themovement of an optical head (not shown).

The data area 902 includes a user area 906 for recording user area and aspare area 907. When there is a defect area (for example, a defectsector) in the user area 906, the user data which is to be recorded inthe defect area is recorded in the spare area 907 instead of a portionof the user area 906 corresponding to the defect area.

The lead-in area 901 includes a first defect management area 904 and asecond defect management area 905 for recording defect managementinformation used for managing a defect area existing in the data area902.

The lead-out area 903 includes a third defect management area 908 and afourth defect management area 909 for recording defect managementinformation used for managing a defect area existing in the data area902, like the lead-in area 901.

The first defect management area 904, the second defect management area905, the third defect management area 908, and the fourth defectmanagement area 909 are respectively located at physically specificpositions in the optical disc 900.

In the first defect management area 904, the second defect managementarea 905, the third defect management area 908 and the fourth defectmanagement area 909, the same information for defect management isrecorded in multiplex. The reason for this is, as described above in thefirst example, that the information recorded in the first, second, thirdand fourth defect management areas 904, 905, 908, and 909 cannot be atarget of defect management. Even if some of the first, second, thirdand fourth defect management areas 904, 905, 908, and 909 have a defectarea and the information recorded in the defect area cannot bereproduced, as long as at least one of the four defect management areasis defect-free, the defect management information recorded in that areacan be normally reproduced. Accordingly, loss of the user data isprevented, which improves reliability. In the second example, theoptical disc 900 includes the four defect management areas 904, 905,908, and 909, but the number of defect management areas may be anynumber of one or more.

In the first defect management area 904, a disc definition structure 911and a defect list 912 for managing N number of defect areas existing inthe data area 902 (N is an integer satisfying N≧0) are recorded.

The disc definition structure 911 is information representing the discstructure, for example, whether or not the disc 900 has been subjectedto defect management. This information also includes informationregarding the spare area 907. The disc definition structure 911 islocated at a physically specific position in the first defect managementarea 904. The disc definition structure 911 has a prescribed size.

The defect list 912 includes a header 921, a first defect entry 922, asecond defect entry 923, . . . , an (N−1)th defect entry 924, an Nthentry 925, and an anchor 927 located at a fixed position in the defectlist 912. The defect list 912 further includes an unused area 926,unlike in the first example. The header 921, the first through Nthentries 922 through 925, and the anchor 927 are located in this order inthe defect list 912.

In the second example, it is assumed that the size of the defect list912 is 4ECC. The size of the defect list 912 is not limited to 4ECC andis arbitrary.

The header 921 includes a defect list identifier 931 which representsthat the area is the defect list 912, a defect entry number 932 whichrepresents the number of defect entries included in the defect list 912,and first update times information 933 which represents the number oftimes which an updated defect list has been recorded in the first defectmanagement area 904. In FIG. 9, the defect entry number 932 is N (N isan integer satisfying N≧0), and the content of the first update timesinformation 933 is M (M is an integer satisfying M≧0). The defect listidentifier 931 may be located, for example, at the start of the header921 shown in FIG. 9.

The header 921 is located at a physically specified position. In thesecond example, the header 921 is located at the start of the defectlist 912. The position of the header 921 in the defect list 912 isarbitrary as long as the header 921, the first through Nth defectentries 922 through 925, and the anchor 927 are located in this order inthe defect list 912.

In the case of the optical disc 900 shown in FIG. 9, the defect entrynumber 932 is N. Thus, the defect list 912 includes the first defectentry 922, . . . , and the Nth defect entry 925. The first defect entry922 includes first defect position information 941 which is positioninformation showing the position of a defect area, and first substituteposition information 942 which is position information showing theposition of a part of the spare area 907 which is usable instead of thedefect area. Likewise, the second defect entry 923 includes seconddefect position information and second substitute position information.The (N−1)th defect entry 924 and the Nth defect entry 925 also havesubstantially the same structure. Here, each of the first defectposition information 941 and the first substitute position information942 is generally a sector number.

The defect entries are generally located such that the defect positioninformation included therein is in an ascending order. Morespecifically, when, for example, the defect position information is asector number, defect position information having the smaller sectornumber is located in the first defect entry as the first defect positioninformation 941. After this, the defect entries are located in the orderof the sector numbers. Defect position information having the largersector number is located in the Nth defect entry 925 as Nth defectposition information.

The defect entries in the defect list 912 do not need to be located inan ascending order. For example, the defect entries may be located suchthat the sector numbers are in a descending order. Alternatively, thedefect entries may be located randomly.

In the unused area 926, currently meaningless information is recorded.Generally, padding data 952 (for example, 0) is recorded in the unusedarea 926. When a new defect area is detected in the user area 906, adefect entry for managing the new defect area is added to the defectlist 912. As a result, the size of the unused area 926 is decreased bythe size of the added defect entry.

The anchor 927 includes second update times information 951 whichrepresents the number of times which the updated defect list has beenrecorded in the first defect management area 904. In FIG. 9, the contentof the second update times information 951 is M (M is an integersatisfying M≧0), and is the same as that of the first update timesinformation 933. As long as the first defect management area 904 isupdated normally, the content of the first update times information 933and the content of the second update times information 951 are identicalto each other.

In this specification, the first and second update times information 933and 951 represent the number of times which the updated defect list hasbeen recorded in the first defect management area 904 (i.e., the numberof times which the defect list 912 has been updated and recorded on theoptical disc 900). The first and second update times information 933 and951 may represent the number of times which the defect list has beenupdated (i.e., the number of times which the defect list has beenupdated in the storage section described below). In the followingdescription, the first and second update times information 933 and 951represent the number of times which the updated defect list has beenrecorded in the first defect management area 904.

The anchor 927 is located at a fixed position in the defect list 912,unlike in the first example. The anchor 927 is preferably located whichis determined based on the position of the header 921. In the secondexample, the anchor 927 is located at the position of the end of thedefect list 912, i.e., at the end of the first defect management area904. Since the size of the defect list 912 is fixed at 4ECC, the anchor927 is located at the end of the fourth ECC block from the start of thedefect list 912. However, as long as the header 921, the list throughNth defect entries 922 through 925, and the anchor 927 are located inthe defect list 912 in this order, the anchor 927 may be fixed at anarbitrary position in the defect list 912.

In the optical disc 900 in the second example, the anchor 927 is locatedat a physically fixed position in the defect list 912. The header 921includes the first update times information 933, and the anchor 927includes the second update times information 951. Since the position ofthe anchor 927 is fixed, the content of the first update timesinformation 933 and the content of the second update times information951 are compared with each other without fail. Accordingly, it can beeasily determined whether or not the defect list 912 has been updatednormally.

The following description will be made with the premise that the opticaldisc 900 has the data structure shown in FIG. 9.

(2) Reproduction/Recording (Update)

The recording and reproduction apparatus 300 shown in FIG. 3 is used forrecording information on the optical disc 900 according to the secondexample and/or reproducing information recorded on the optical disc 900.Unlike in the first example, the control section 301 in the secondexample has only an inherent defect list identifier for identifying thedefect list 912 in the optical disc 900 stored thereon. The content(value) of the inherent defect list identifier is correct and is notrewritable. The description of the recording and reproduction apparatus300 shown in FIG. 3 is provided in the first example and will not berepeated here.

(2-1) Defect Management Processing for Specifying the Latest Defect List

Next, with reference to FIG. 3, the operation of defect managementprocessing for specifying the latest defect list performed by therecording and reproduction apparatus 300 will be described.

The control section 301 executes the defect management processing. Thecontrol section 301 follows the procedure of the defect managementprocessing to request the recording and reproduction section 302 toreproduce the information of the disc definition structure 911 locatedat the start of the first defect management area 904 and store thereproduced information from the disc definition structure 911 in thestorage section 303.

Upon the request from the control section 301, the recording andreproduction section 302 reproduces the information of the discdefinition structure 911 from the optical disc 900 and stores theinformation in the storage section 303. The recording and reproductionsection 302 reports to the control section 301 that the reproduction andstorage of the information of the disc definition structure 911 has beencompleted.

Upon receiving the report from the recording and reproduction section302, the control section 301 checks whether or not the optical disc 900has been subjected to defect management, based on the information of thedisc definition structure 911 stored in the storage section 303.

When confirming that the optical disc 900 has been subjected to defectmanagement, the control section 301 requests the recording andreproduction section 302 to reproduce the header 921 located at a fixedposition of the defect list 912 (in the example of FIG. 9, at the startof the defect list 912) recorded in the first defect management area 904and store the reproduced header 921 in the storage section 303.

Upon the request from the control section 301, the recording andreproduction section 302 reproduces the header 921 located at the startof the defect list 912 recorded in the first defect management area 904and store the reproduced header 921 in the storage section 303. Therecording and reproduction section 302 reports to the control section301 that the reproduction and storage of the header 921 has beencompleted.

Upon receiving the report from the recording and reproduction section302, the control section 301 compares the content of the inherent defectlist identifier initially stored in the control section 301 with thecontent of the defect list identifier 931 included in the header 921stored in the storage section 303 to check whether or not the storedinformation is the header 921 in the defect list 912.

When the two contents compared match each other, the control section 301determines that the stored information is the header 921 in the defectlist 912 and proceeds with the defect management processing. When thetwo contents compared do not match each other, the control section 301determines that updating of the first defect management area 904 failed(abnormal defect management area) and terminates the defect managementprocessing. The two contents compared do not match each other when, forexample, there is a defect area in the first defect management area 904and thus information cannot be read therefrom.

In order to confirm the content of the first update times information933 and the content of the second update times information 951 in thefirst defect management area 904, the control section 301 requests therecording and reproduction section 302 to reproduce the anchor 927located at the fixed position in the defect list 912 (in FIG. 9, at theend of the fourth ECC block from the start of the defect list 912) andstore the reproduced anchor 927 in the storage section 303.

Upon the request from the control section 301, the recording andreproduction section 302 reproduces the anchor 927 located at thedesignated position in the defect list 912 and stores the reproducedanchor 927 in the storage section 303. The recording and reproductionsection 302 reports to the control section 301 that the reproduction andstorage of the anchor 927 has been completed.

The control section 301 compares the content of the first update timesinformation 933 included in the header 921 with the content of thesecond update times information 951 included in the anchor 927 stored inthe storage section 303.

When the two contents compared match each other, the control section 301determines that the first defect management area 904 has been updatednormally, and proceeds with the defect management processing.

When the two contents compared do not match each other, the controlsection 301 determines that updating of the first defect management area904 failed (abnormal defect management area) and terminates the defectmanagement processing. The two contents compared do not match each otherwhen, for example, the recording and reproduction apparatus 300 isturned off while the first through Nth defect entries 922 through 925 inthe defect list 912 are being updated. In this case, the content of thefirst update times information 933 included in the header 921 does notmatch the content of the second update times information 951 included inthe anchor 927.

The control section 301 performs substantially the same processing foreach of the second defect management area 905, the third defectmanagement area 908 and the fourth defect management area 909.

After checking whether or not each of the first through fourth defectmanagement areas 904, 905, 908 and 909 is a normal defect managementarea, the control section 301 specifies the latest defect managementarea among the defect management areas which have been determined to benormal, as follows. The control section 301 makes a comparison of thefirst update times information 933 recorded in the defect managementareas which have been determined to be normal, and specifies the defectmanagement area having the largest number of updates as the latestdefect management area. The defect list recorded in the specified latestdefect management area is specified as the latest defect list.

The second update times information 951 included in the anchor 927 maybe used for specifying the latest defect management area instead of thefirst update times information 933.

The control section 301 requests the recording and reproduction section302 to reproduce the defect list recorded in the specified latest defectmanagement area and store the reproduced defect list in the defect listarea saved in the storage section 303.

Upon the request from the control section 301, the recording andreproduction section 302 reproduces the defect list recorded in thespecified latest defect management area and stores the reproduced defectlist in the defect list area in the storage section 303. The recordingand reproduction section 302 reports to the control section 301 that thereproduction and storage of the defect list has been completed.

Thus, the operation of defect management processing for specifying thelatest defect list performed by the recording and reproduction apparatus300 is completed.

Using the specified latest defect list, the user data recorded in thedata area 902, for example, can be reproduced. In this case, the controlsection 301 requests the recording and reproduction section 302 toreproduce the user data based on the latest defect list and store thereproduced user data in the storage section 303.

Upon the request from the control section 301, the recording andreproduction section 302 reproduces the user data from the data area 902and stores the reproduced user data in the storage section 303.

Information recording may be performed using the specified latest defectlist.

FIG. 10 shows a procedure of defect management processing for specifyingthe latest defect list in the second example. The defect managementprocessing is executed by the control section 301. Hereinafter, eachstep of the procedure of defect management processing will be described.The procedure of defect management processing is started after it isconfirmed that the optical disc 900 has been subjected to defectmanagement. Whether or not the optical disc 900 has been subjected todefect management is determined based on the disc definition structure911 in the optical disc 900.

Step S1001: The defect list identifier 931, the defect entry number 932and the first update times information 933 included in the header 921are reproduced. The content of the reproduced defect list identifier 931is compared with the content of the inherent defect list identifier. Theinherent defect list identifier identifies the defect list 912 in theoptical disc 900. The inherent defect list identifier has a correctvalue which is not rewritable. The inherent defect list identifier maybe initially stored in the control section 301. When the two contentscompared match each other, the defect management processing advances tostep S1002. When the two contents compared do not match each other, thedefect management processing advances to step S1003.

Step S1002: When the content of the defect list identifier 931 and thecontent of the inherent defect list identifier are determined to matcheach other in step S1001, the reproduced information is determined to bethe header 921 in the defect list 912. The anchor 927 located at a fixedposition (in FIG. 9, at the position of the fourth ECC block from thestart of the defect list 912) is reproduced. The content of the firstupdate times information 933 included in the header 921 is compared withthe content of the second update times information 951 included in theanchor 927. When the two contents compared are determined to match eachother, the defect management processing advances to step S1004. When thetwo contents compared are determined not to match each other, the defectmanagement processing advances to step S1003.

Step S1003: When the content of the defect list identifier 931 and thecontent of the inherent defect list identifier are determined not tomatch each other in step S1001, or when the content of the first updatetimes information 933 and the content of the second update timesinformation 951 are determined not to match each other in step S1002,updating of the first defect management area 904 is determined to havefailed (abnormal defect management area), and the defect managementprocessing for the first defect management area 904 is terminated. Thedefect management processing advances to step S1005.

Step S1004: When the content of the first update times information 933and the content of the second update times information 951 aredetermined to match each other in step S1002, the first defectmanagement area 904 is determined to have been updated normally. Then,the defect management processing advances to step S1005.

Step S1005: It is determined whether or not the operations in stepsS1001 through S1004 have been performed for all the defect managementareas in the optical disc 900. When the operations in steps S1001through S1004 have not been performed for all the defect managementareas, the defect management processing returns to step S1001. When theoperations in steps S1001 through S1004 have been performed for all thedefect management areas, the defect management processing advances tostep S1006.

Step S1006: The latest defect list is specified. More specifically, thelatest defect management area among the defect management areasdetermined to be normal is specified, as follows. A comparison is madeof the first update times information (or the second update timesinformation) recorded in the defect management areas determined to benormal, and the defect management area having the largest number ofupdates is specified as the latest defect management area. The defectlist recorded in the specified latest defect management area isspecified as the latest defect list.

When the latest defect list of the optical disc 900 is specified bysteps S1001 through S1006, the defect management processing iscompleted. Using the latest defect list obtained in step S1006, the userdata recorded in the data area 902, for example, can be reproduced.

(2-2) Defect Management Processing for Updating the Latest Defect List

Returning to FIG. 3, the operation of defect management processing forupdating the latest defect list performed by the recording andreproduction apparatus 300 will be described. In the following example,the defect list is updated when another defect area is detected whilethe user data is being recorded in the data area 902 of the optical disc900, or when a portion of the user area 906 which was previouslydetermined to be a defect area is determined to be a normal defect areawhile the user data recorded in the data area 902 is being reproduced.Throughout this specification, a “normal defect area” is defined to meanan area which was previously determined to be a defect area butcurrently has no defect and allows information to be recorded thereinand/or allows information therein to be reproduced. An area which waspreviously determined to be a defect area is currently determined to bea normal defect area when, for example, the defect is caused by dust orstain such as a fingerprint on the surface of the optical disc. In thiscase, when the user cleans the surface of the optical disc to remove thedust or stain, the area in which the dust or stain existed (i.e., thearea which was previously determined to be a defect area) is currentlydetermined to be a normal area usable for recording/reproduction.

The storage section 303 stores the latest defect list. The latest defectlist may be located in the defect list area in the storage section 303.The latest defect list includes the latest header, P number of latestdefect entries (P is an integer satisfying P≧0 where P=N or P≠N), andthe latest anchor. The latest header, the P number of latest defectentries, and the latest anchor are located in the latest defect list inthis order. The latest header is located at a fixed position in thelatest defect list. The latest anchor is also located at a fixedposition in the latest defect list. The latest header includes thelatest defect list identifier, the first latest update times informationand the latest defect entry number P. The content of the latest defectlist identifier is always the same as that of the inherent defect listidentifier stored in the control section 301. The latest anchor includesthe second latest update times information which has the same content asthat of the first latest update times information. It is assumed thatthe P number of latest defect entries are arranged in an ascending orderof the defect position information (defect sector numbers). The latestdefect list may include an unused area. It is not always necessary thatthe latest header includes the latest defect list identifier.

The above-described arrangement of the latest header and the P number oflatest defect entries and the latest anchor is merely an example. Thearrangement of the latest header and the P number of latest defectentries and the latest anchor in the latest defect list is arbitrary.

The control section 301 executes the defect management processing. Thecontrol section 301 requests the recording and reproduction section 302to determine whether (a) another defect area exists in the data area902, (b) a defect area which was previously determined to be a defectarea is currently a normal defect area, or (c) neither (a) nor (b) isthe case. Whether or not another defect area exists in the data area 902is determined by, for example, comparing a signal obtained byreproducing data immediately after user data is recorded with a signalrepresenting user data to be recorded. When these signals match eachother, the user data is determined to have been normally recorded in thedata area 902. When these signals do not match each other, it isdetermined that the user data has not been normally recorded in the dataarea 902 and another defect area exists in the data area 902.

When determining that another defect area exists in the data area 902 orthat the area which was previously determined to be a defect area iscurrently a normal defect area, the control section 301 updates thelatest defect list stored in the storage section 303.

Specific procedures of updating the latest defect list will bedescribed. There are three cases of updating the latest defect list,namely, (i) addition of a defect entry, (ii) deletion of a defect entry;and (iii) change of a defect entry. Each of these cases will bedescribed one by one.

(i) Addition of a Defect Entry

When it is determined that another defect area exists in the user area906, a defect entry including the position information on the positionof the another defect area is added to the latest defect list. Based onthe defect position information on the detected defect area, the controlsection 301 determines the position of the defect entry to be added. Thecontrol section 301 shifts the other defect entries and the latestanchor existing subsequent to the determined position toward the unusedarea, and adds the defect entry including the position information onthe another defect area at the determined position. As a result, the Pnumber of latest defect entries are updated to P′ number of latestdefect entries (P≠P′, P<P′).

Following the addition of the defect entry, the control section 301updates the latest defect entry number from P into P′. In this case, thelatest defect entry number is increased by the number of the addeddefect entries (i.e., by the number of the detected defect sectors).

After the P number of latest defect entries and the latest defect entrynumber Pare updated, the control section 301 increments, by one, thecontent of the first latest update times information included in thelatest header and the content of the second latest update timesinformation included in the latest anchor.

(ii) Deletion of a Defect Entry

When an area which was previously determined to be a defect area iscurrently determined to be a normal defect area, the control section 301deletes the defect entry including the position information on the areadetermined to be the normal defect area. The control section 301 thenshifts the defect entries located subsequent to the deleted defect entrytoward the latest header by the size of the deleted defect entry. Theunused area is expanded by the size of the deleted defect entry, and thecontrol section 301 records padding data (for example, 0) in theexpanded portion of the unused area. As a result, the P number of latestdefect entries are updated to P′ number of latest defect entries (P≠P′,P>P′).

Following the deletion of the defect entry, the control section 301updates the latest defect entry number included in the latest headerfrom P into P′. In this case, the latest defect entry number isdecreased by the number of the deleted defect entries (i.e., by thenumber of the defect sectors determined to be normal).

After the P number of latest defect entries and the latest defect entrynumber Pare updated, the control section 301 increments, by one, thecontent of the first latest update times information included in thelatest header and the content of the second latest update timesinformation included in the latest anchor.

(iii) Change of a Defect Entry

The operation in this case is the same as the operation described in thefirst example, and will not be repeated here.

The operations of (i) through (iii) are performed by the control section301 for the latest defect list stored in the storage section 303. As inthe first example, in the case where the first and second update timesinformation 933 and 951 represent the number of times which the updatedlatest defect list has been recorded in the first defect management area904, the first and second latest update times information may each beincremented by one only once before the updated latest defect list isrecorded in the first defect management area 904. By contrast, in thecase where the first and second update times information 933 and 951represent the number of times which the latest defect list has beenupdated in the storage section 303, the first and second latest updatetimes information may be incremented by one each time the latest defectentries and the latest defect entry number are updated.

The control section 301 requests the recording and reproduction section302 to record the latest defect list updated in the storage section 303in the first defect management area 904 of the optical disc 900. Forexample, the control section 301 requests the recording and reproductionsection 302 to record the updated latest header, the updated P′ numberof latest defect entries, and the updated latest anchor in the firstdefect management area 904 in this order.

Upon the request from the control section 301, the recording andreproduction section 302 records the updated latest defect list in thefirst defect management area 904. The updated defect list replacing thedefect list 912 is recorded in the first defect management area 904 inthe order of the latest header replacing the header 921, the latestdefect entries replacing the first through Nth defect entries 922through 925, and the latest anchor replacing the anchor 927. Therecording and reproduction section 302 reports to the control section301 that the recording of the updated latest defect list in the firstdefect management area 904 has been completed. Unlike in the firstexample, the anchor 927 is located at the fixed position, i.e., at theend of the fourth ECC block from the start of the defect list 912 in theoptical disc 900 in the second example. Therefore, even when the totalsize of the header 921 and the defect entries in the defect list 912 isaccommodated in 1ECC size, data of at least two ECC blocks, i.e., thedata for the first ECC block and the data for the fourth ECC block needto be recorded.

The control section 301 requests the recording and reproduction section302 to record the latest defect list updated in the storage section 303in each of the second through fourth defect management areas 905, 908and 909. More specifically, again, the control section 301 requests therecording and reproduction section 302 to record the updated latestheader, the updated latest defect entries, and the updated latest anchorin this order in the second through fourth defect management areas 905,908 and 909.

Upon the request from the control section 301, the recording andreproduction section 302 records the updated latest defect list in eachof the second through fourth defect management areas 905, 908 and 909.

Thus, the operation of defect management processing for updating thelatest defect list performed by the recording and reproduction apparatus300 is completed.

The order of recording the updated latest defect list is not limited tothe above-described order of the latest header, the P′ number of latestdefect entries, and the latest anchor. As long as the header 921, the Nnumber of defect entries 922 through 925, and the anchor 927 are locatedin this order in the defect list 912, the control section 301 mayrequest the recording and reproduction section 302 to record the updatedlatest anchor, the P′ number of latest defect entries, and the latestheader in this order in each of the first through fourth defectmanagement areas 904, 905, 908 and 909, and the recording andreproduction section 302 may record the updated latest defect list ineach of the first through fourth defect management areas 904, 905, 908and 909 upon the request from the control section 301.

Returning to FIG. 5, a procedure of defect management processing forupdating the latest defect list in the second example will be described.The defect management processing is executed by the control section 301.The operations in steps S501 through S503 and S505 are substantially thesame as those of the first example, and will not be repeated here.

Step S504: The updated latest defect list is recorded in the firstdefect management area 904 of the optical disc 900. For example, theupdated latest header, the updated P′ number of latest defect entries,and the updated latest anchor are recorded in the first defectmanagement area 904 in this order. As long as the header 921, the Nnumber of defect entries 922 through 925, and the anchor 927 are locatedin this order in the defect list 912, the updated latest anchor, theupdated P′ number of latest defect entries, and the updated latestheader may be recorded in this order in the first defect management area904. In the optical disc 900, the anchor 927 is located at the fixedposition in the defect list 912 (in FIG. 9, at the end of the fourth ECCblock from the start of the defect list 912). Therefore, even when thetotal size of the header 921 and the defect entries in the defect list912 is accommodated in 1ECC size, data of at least two ECC blocks, i.e.,the data for the first ECC block and the data for the fourth ECC blockare recorded.

As described above, the arrangement of the latest header, the P′ numberof latest defect entries and the latest anchor in the latest defect listis arbitrary. The updated latest defect list is recorded in each of thefirst through fourth defect management areas 904, 905, 908 and 909 ofthe optical disc 900 as follows. Such that the updated latest header islocated at the position of the header 921, the updated P′ number oflatest defect entries are located at the positions of the defect entries922 through 925, and the updated latest anchor is located at theposition of the anchor 927, the updated latest defect list is recordedin each of the first through fourth defect management areas 904, 905,908 and 909 in the order of the updated latest header, the updated P′number of latest defect entries, and the updated latest anchor or in theorder of the updated latest anchor, the updated P′ number of latestdefect entries, and the updated latest header.

In the above description, the updated latest defect list is recorded onthe optical disc 900 shown in FIG. 9 where the optical disc 900 has beensubjected to defect management. Next, recording of the updated latestdefect list on an optical disc in an initial state immediately afterbeing shipped from the plant will be described.

An optical disc in an initial state is assumed to have the samestructure as that shown in FIG. 9 except that, for example, the defectlist 912 (FIG. 9) has no information. In such optical disc, no defectlist identifier for identifying the defect list is recorded. Therefore,in the case where the latest defect list does not include the latestdefect list identifier, the defect management processing of recordingthe latest defect list includes the process of recording the defect listidentifier in addition to the process of recording the latest defectlist in the defect management area. In the case where the latest defectlist includes the latest defect list identifier, no detailed explanationwill be given since the processing was described above with reference toFIG. 5.

The control section 301 requests the recording and reproduction section302 to record the latest defect list stored in the storage section 303in the defect management area of the optical disc and to record theinherent defect list identifier, which is initially stored in thecontrol section 301, in the defect management area of the optical disc.More specifically, the inherent defect list identifier is recorded inthe defect management area so as to be located at the start of theheader 921. In this case, an arbitrary value is recorded as the latestdefect entry number and as the latest defect entry of the latest defectlist which respectively correspond to the defect entry number 932 andthe first through Nth defect entries 922 through 925. As the firstupdate times information and as the second update times information, forexample, 0 or 1 is recorded. The values to be recorded as the first andsecond update times information are arbitrary as long as the values areequal to each other and represent that recording has been performed onan optical disc in the initial state only once.

The method for recording the defect list identifier in the defectmanagement area is not limited to the above-described method. Forexample, the inherent defect list identifier already stored in thecontrol section 301 is given as the latest defect list identifier at thestart of the latest header of the latest defect list stored in thestorage section 303. As the defect management processing performed on anoptical disc in the initial state, the latest defect list including thelatest defect list identifier obtained in this manner may be recorded inthe defect management area.

This process of defect management processing is performed in steps S504and S505 in FIG. 5.

In the second example, it is accurately determined whether or not thedefect management area has been updated normally. This will be describedbelow. In the following explanation, the optical disc 900 is used.

Specific Example 1 When a Defect Entry is Added

FIG. 11 shows data structures of a defect list in various states. Part(a) shows a data structure of a pre-update defect list. Part (b) shows adata structure of a defect list which was updated normally. Part (c)shows a data structure of a defect list which was not updated normally.

FIG. 11 shows the case where another defect area (defect sector) isdetected in the user area 906 and one defect entry is added. Theaddition of the defect entry is performed as described above withreference to FIGS. 3 and 5.

Part (a) of FIG. 11 shows a data structure before the defect list isupdated. The defect list shown in part (a) is the same as the defectlist 912 shown in FIG. 9. The defect list includes a first defect entry,. . . , and an Nth defect entry. The defect entry number is N, and thecontent of each of the first update times information and the secondupdate times information is M.

Part (b) of FIG. 11 shows a data structure after the defect list isupdated normally (one defect entry is added normally). When one defectentry is added normally to the defect list, the defect list includes thefirst defect entry, . . . , the Nth defect entry, and an (N+1)th defectentry. The number of defect entries is increased by one from the statein part (a) of FIG. 11. The defect entry number is updated from N toN+1. The content of each of the first update times information and thesecond update times information is updated from M to M+1.

Following the addition of the defect entry, the size of the unused areais decreased by the size of the added defect entry like Specific example1, but the position of the anchor is fixed. The content of the firstupdated times information matches the content of the second updatedtimes information. Thus, it can be determined that the defect list hasbeen updated normally.

Part (c) of FIG. 11 shows a data structure of a defect data in the casewhere the update failed before the anchor is recorded. The failureoccurs when, for example, the recording and reproduction apparatus 300is turned off while the defect list is being updated. In part (c) ofFIG. 11, the defect list includes the first defect entry, and the Nthdefect entry, like in part (a) of FIG. 11. Although the defect listincludes the same defect entries as those of part (a) of FIG. 11, thedefect entry number is updated from N to (N+1). The content of the firstupdate times information is updated from M to (M+1). However, thecontent of the second update times information is M like in part (a) ofFIG. 11. Since the content of the first updated times information doesnot match the content of the second updated times information, it isdetermined that the updating of the defect list failed.

In the case where a defect entry is changed or a defect entry isdeleted, it can be determined whether or not the defect list has beenupdated normally by comparing the content of the first update timesinformation and the content of the second update times information insubstantially the same manner.

In the second example, the anchor 927 includes only the second updatetimes information 951. As in the first example, the anchor 927 may alsoinclude an anchor identifier for identifying the anchor in the defectlist 912. In this case also, the same effect as described in the secondexample can be provided.

In the second example, the header 921 includes the defect listidentifier 931. The header 921 is located at a physically specifiedposition in the optical disc 900 and therefore does not need to includethe defect list identifier 931. Even without the defect list identifier931, the same effect as described in the second example can be provided.

As described above, according to the second example of the presentinvention, the information recording medium 900 includes the data area902 for recording user data, and the defect management areas 904, 905,908 and 909 for recording a defect list used for managing N number ofdefect areas existing in the data area 902 (N is an integer satisfyingN≧0). The defect list 912 includes the header 921, the N number ofdefect entries respectively including the position information on thepositions of the N number of defect areas, and the anchor 927 located ata fixed position in the defect list 912. The header 921 includes thefirst update times information 933, and the anchor 927 includes thesecond update times information 951.

Since the anchor 927 is located at the fixed position, other informationis never erroneously reproduced as the anchor 927. Namely, the contentof the first update times information 933 and the content of the secondupdate times information 951 can be compared with each other withoutfail. Accordingly, it can easily be determined whether or not the defectlist 912 has been updated normally.

Again, since the anchor 927 is located at the fixed position, it is notnecessary to calculate the position of the anchor 927 and check whetheror not the anchor 927 is located at the calculated position as isnecessary in the first example, in order to reproduce the anchor 927.Therefore, the processing of defect management can be simplified andimproved in speed.

It is not necessary to provide a header for each 1ECC size even when thesize of the defect list 912 is not accommodated in 1ECC size. Thus, theprocessing efficiency of updating the defect list 912 is improved. Sincethe header is not interposed between the two defect entries, defectentries can be, for example, searched for, added and deleted easily.

As described above, an information recording medium according to thepresent invention includes a data area for recording user data and adefect management area for recording a defect list used for managing Nnumber of defect areas (N is an integer satisfying N≧0) existing in thedata area. The defect list includes a header, N number of defect entriesrespectively including the position information on the positions of theN number of defect areas, and an anchor. The header, the N number ofdefect entries, and the anchor are located in this order in the defectlist. Owing to such a structure, the size of the defect list isvariable, and therefore the processing speed is improved in accordancewith the size of the defect list.

With the information recording medium according to the presentinvention, the header includes a defect list identifier for identifyingthe defect list, first update times information representing the numberof times which the defect list has been updated, and a defect entrynumber representing the number of defect entries. The anchor includes ananchor identifier for identifying the anchor of the defect list, andsecond update times information representing the number of times whichthe defect list has been updated. It is not necessary to provide aheader for each 1ECC size even when the size of the defect list is notaccommodated in 1ECC size. Thus, the processing efficiency of updatingthe defect list is improved. Since the header is not interposed betweenthe two defect entries, defect entries can be, for example, searchedfor, added and deleted easily.

The content of the anchor identifier is different from any of the defectlist identifier, the defect entry number, the first update timesinformation, the defect entries, or the second update times information.As such, even when a defect entry is deleted, the information which iserroneously read as the anchor identifier never matches the content ofthe inherent anchor identifier. Therefore, the defect list is noterroneously determined to have been updated normally when it has notbeen updated normally.

Various other modifications will be apparent to and can be readily madeby those skilled in the art without departing from the scope and spiritof this invention. Accordingly, it is not intended that the scope of theclaims appended hereto be limited to the description as set forthherein, but rather that the claims be broadly construed.

1. An information recording medium, comprising: a data area forrecording user data, a lead-out area in an outer side of the medium thanthe data area, and a plurality of defect management areas for recordinga defect list for managing N number of defect areas existing in the dataarea, where N is an integer satisfying N≧0; wherein: the lead-out areaincludes: a third defect management area and a fourth defect managementarea, the defect list includes: a header located at a fixed position inthe defect list, N number of defect entries respectively includingposition information on positions of the N number of defect areas, andan anchor; the header, the N number of defect entries, and the anchorare located in this order in the defect list; the header includes: adefect list identifier for identifying the defect list, first updatetimes information representing the number of times which the defect listhas been updated, and a defect entry number representing the number ofthe N number of defect entries; and the anchor includes: an anchoridentifier for identifying the anchor of the defect list, and secondupdate times information representing the number of times which thedefect list has been updated.
 2. A reproduction apparatus forreproducing information recorded on an information recording mediumaccording to claim
 1. 3. A recording apparatus for recording informationon an information recording medium according to claim 1.